Please note this thread has been inactive for 90 days. For the best results, please start a new thread.
Results 1 to 24 of 24

Thread: Testing wires

  1. #1
    Chief Petty Officer
    Join Date
    Sep 2010
    Posts
    630

    Default Testing wires

    About ready to redo the wiring on the old boat. I first want to trace my panel main ground since this project appears to have some confusion under the cloak of sheathing. I don't have a multimeter, but have a cheap 12v tester from HFT.

    Before I disassembled the old console panel, one black wire was jumped to the switches and not working fuel gauge(I have fuel diagram)

    Nothing is connected to a battery yet. I first want to connect the engine red and black only. At that point, what do I need to do to check the black ground at the panel to see if this connection supplies my panel main grounding using this tester?

    The tester is a CEN-TECH circuit tester, has a single probe and a cord with a clamp. The instructions ask to connect the clamp to the battery post(NEG in this case) and touch the wire(main black at panel) with the probe tip. If it lights up, then OK.

    Sound right?

    This is an old boat with some confusion, sheathed runs, unidentified wires, odd colors in odd places, and about every issue that requires tracing before connecting.

    Please keep in mind this boat at the battery does not have a common place(buss) where a collection of grounds are obvious. Instead, the grounds for the bilge, fuel tank, and stern light disappear into a merging highway of cable and are probably spliced into the wire leading to the panel, I hope.

    Funny thing, the bow light ground flows toward the panel, but disappears also into a cable run, so somewhere under cover is a collection of spliced grounds??

  2. #2
    Supreme Mariner Silvertip's Avatar
    Join Date
    Sep 2003
    Location
    Midwest
    Posts
    25,770

    Default Re: Testing wires

    That is a voltage tester and is typically used to test circuits OTHER than ground. With the light connected to ground, putting the probe on the other end of a ground circuit would not work since there is no current flow. However, you can do it this way:

    1) Connect the clip to the POSITIVE terminal on the battery.
    2) DISCONNECT the ground wire from wherever you want to test it.
    3) Touch the probe to that wire.
    4) Light lights, you have a ground. No light = no ground.

    Keep in mind that your boat probably has two smaller gauge wires (probably #8 or #10 gauge) that run from the battery to the helm. If not, all power runs through the engine harness.

  3. #3
    Chief Petty Officer
    Join Date
    Sep 2010
    Posts
    630

    Default Re: Testing wires

    Thanks, will try that. I do have a red wire that connects to the battery, and into a circuit breaker, then will test the red wire at the panel to see if that is my panel feed. It does not have a separate ground to match which led me to think that the panel ground is coming from the engine ground?

    In other words two red and one black on the battery. If your method works, it will confirm my panel ground is spliced in somewhere through the engine connection to the main battery.

    If so, then can I use your method to trace other wires?

    Assume the test concludes that the panel ground and the panel main red feed work when the engine red and black, plus the additional red are connected to the battery. That gives me power and ground to finish wiring the panel which has a brand new pre-wired 5 switch with breaker/fuse built in. All I would need is to follow their instructions to join the colored wires for bilges, horn, NAV, and courtesy lights.

    The kit also includes a ground bus. The instructions say to connect the main black to the bus, then the black from each switch to the bus.

    My speedo is a pitot, and only one white wire attached to it. I figure this is the backlight, and would splice power of the bow light feed so it lights only when the bow light is on. How do I make sure that white wire is backlight?

    The current wiring of the fuel tank is odd. I have the diagram generously provided on this site. I have the pink wire at the panel, and will follow the diagram for the fuel gauge except there is no solid evidence of IGN feed to the panel to complete the wiring so it only reads when the key is in the ON position. I will light it though like the speedo light. Question:

    If the fuel gauge has to get power from the same source as panel switches, what draw on the battery is there, and is it significant to drain the battery in a short time? There is also one additional red wire at the panel, looks newer than 30 years old, looks like it was snipped clean or never used. How would I trace this red wire to its source? Could it be the IGN feed I need for the gauge?

    Don't mean to ramble.

    If I connect as described, test the other unused red wire and it is not hot, then turn the IGN switch to ON, then test again, it would light if it was the IGN feed?

  4. #4
    Supreme Mariner Silvertip's Avatar
    Join Date
    Sep 2003
    Location
    Midwest
    Posts
    25,770

    Default Re: Testing wires

    I can assure you that if you do not have a ground wire from the helm to the battery that ground MUST be obtained through the engine harness which is a NO-NO. Yes it works, but that harness probably does not contain a #8 or #10 ground wire. Ground wires MUST be the same size or larger than the red wire (positive) that feeds a circuit. Besides, a failure anywhere in the engine harness means every accessory on the boat dies including a marine radio so you lose communication in an emergency.

    As as I said, the tester you have is typcially used to test OTHER than ground. The procedure I posted is to test for the GROUND wire. DO NOT use that process to test OTHER than ground. To test those circuits you connect the clip to the NEGATIVE terminal of the battery and then touch the other circuits to see if voltage is present.

  5. #5
    Chief Petty Officer
    Join Date
    Nov 2010
    Location
    North Carolina
    Posts
    476

    Default Re: Testing wires

    Sounds like you a mess of confusion!

    Disconnect the engine harness and battery connections
    One thing I have use to trace wires:

    Use a 9v battery, they don't have enough current to hurt much but will help show 'continuity'.

    As previously posted, connecting the test light leads backwards can be used to check for common ground wires.

    One thing I would suggest, if you're re-doing the wiring, DON'T TRY TO FIGURE OUT WHAT IS THERE...you could spend hours trying to figure out IT'S ALL WRONG...old boats had everybody and their mother try their handy-work.....take plenty of notes, use masking tape and perminant marker to mark connections and remove EVERYTHING, start un-doing all the tape/connections and 'other stuff'......remove the mystery, sheathed runs, unidentified wires, odd colors in odd places, merging highway of cable and start over.

    http://forums.iboats.com/engine-frequently-asked-questions-faq/generic-boat-wiring-diagram-silvertip-186986.html

    Nice looking boat/project!

  6. #6
    Chief Petty Officer
    Join Date
    Sep 2010
    Posts
    630

    Default Re: Testing wires

    Understand, maybe I am making this sound like a mess when it isn't.

    The initial confusion is from a basic concern of electricity. Always led to believe one red and one black.

    If I have an engine red and black, and a trim motor red and black, then I should have a panel red and black. The only way to find out how the panel was grounded is to trace back where the single black wire at the panel originates.

    One would think very near to the red wire at the battery that runs through a 15amp breaker. I am also sure somewhere it is joined with the anchor light, bilge, and fuel tank grounds.

    I can simply run a brand new black wire from the battery to the panel, by doing that, I need to locate the grounds for the aforementioned items to get them grounded.

    I am not going to rip apart all the wiring because all indications show only the fuel tank/gauge wiring was botched.

  7. #7
    Chief Petty Officer
    Join Date
    Sep 2010
    Posts
    630

    Default Re: Testing wires

    Quote Originally Posted by Silvertip View Post
    That is a voltage tester and is typically used to test circuits OTHER than ground. With the light connected to ground, putting the probe on the other end of a ground circuit would not work since there is no current flow. However, you can do it this way:

    1) Connect the clip to the POSITIVE terminal on the battery.
    2) DISCONNECT the ground wire from wherever you want to test it.
    3) Touch the probe to that wire.
    4) Light lights, you have a ground. No light = no ground.

    Keep in mind that your boat probably has two smaller gauge wires (probably #8 or #10 gauge) that run from the battery to the helm. If not, all power runs through the engine harness.
    Do I need to connect the red/black engine wires to the battery first?

    Here is basic inventory of what the boat has. Disregarding anything that gets connected with an inline direct to the battery such as VHF and a fish finder, the following core wiring exists:

    At the main battery, a red/black to the engine, a red/black to the trim motor, and a red connected to a 15 amp breaker that should test out as my feed to the panel.

    The trim controls have a 3 way wire from the control box to the trim motor(blue-green-purple)

    At the panel is a black wire, a red wire(more reddish orange and matches the color at the battery breaker), a pink sender wire, a brown bilge wire, a browinsh horn wire, blue and green NAV light wires, and another mysterious red wire clean cut and/or never used?

    Connected(riding along) with the red wire at the battery that appears to be my panel feed is a purple wire and a white with green stripe wire. Not sure how these were connected at purchase but they have post rings.

    Coming from the fuel tank is a harness that starts with a black wire and a pink sender on the female side of the clip. Also coming out of that female side is a blue wire that has a clamp on it and was at one time connected to the battery, guessing the negative post. On the male side of the clip is the continuation of the pink sender, black ground, and white with green stripe.

    The only wire that makes it to the panel is the pink sender. Where did the black ground terminate and where did the white with green stripe wire terminate.

    The 3 main items that cause the confusion are the panel ground, the fuel harness, and the purple wire in the trio at the battery.

    If you have one-half of a harness connection that includes 3 wires, one black acting as a ground to the fuel tank, one pink sender, and one blue wire, and that blue wire finds its way to the negative battery post, can this be construed as the blue connecting the ground to the tank and sender?

    If on the other half of that harness is a pink sender, a black ground, and a mysterious white wire with green stripe, does this harness continue the flow as described? Can this black be the ground at the panel via the blue wire connection to the NEG post, to the tank, and forward to the helm?



    As far as the purple wire, someone mentioned that the 1979 Merc tilt/trim used its own power system for IGN, and stated that was how the up/down/trailer was fed. If that ends up being accurate, that leaves the matching white with green stripe wire of the trio unanswered, but curious as to why the same color is involved with the fuel harness?

    If that wire appeared at the helm as an odd way of powering up the fuel gauge directly, then I wouldn't understand that scheme.

    Thus, it is a process of elimination trying to avoid trial and error and the use of some type of tester and in need of the best tracing procedure.

  8. #8
    Chief Petty Officer
    Join Date
    Sep 2010
    Posts
    630

    Default Re: Testing wires

    OK, picked up an inexpensive digital Multimeter, now what?

    First want to check the panel feeds. In other words, connect what I think is the red to the battery and wacky misdirected ground also. At the panel, I have the red and black wires and want to see if these are my panel source of power and ground. I suppose I set the meter to 20 on the V side and probe red to red and black to black?

    Let's say it reads 12 volts or something in that range. Does this mean I have found the correct battery connection to the panel?

    Next, disconnect my battery and go OHMS

    How do I use this Multimeter to trace wires? Considering each end of the wire is further than the probes can reach, what use is this device? These look like they are best for PC boards!!

    I have read various tutorials and it seems they don't apply to what I am trying to solve.

    Can someone also shed light on why certain boat harnesses have different colors on each side of the connector clamp, and often times more on one side, less wires on the other? Why would they change?

    In the meanwhile, gonna return this device and get a porcelain light fixture instead.............lol

  9. #9
    Supreme Mariner Silvertip's Avatar
    Join Date
    Sep 2003
    Location
    Midwest
    Posts
    25,770

    Default Re: Testing wires

    Resistance (Ohms) Testing: Set the selector to Rx1. To test a single run of wire you need to make sure there is nothing else connected to that circuit along the line. This is a simple end to end test of a single length of wire (say the "S" (sender) wire from the fuel tank sender to the "S" terminal on the gauge. To test that wire you would disconnect the EITHER the tank end or the OR the gauge end. Touch one probe to the gauge end and the other to the tank end. Probes too short and wonder what to do? Come on Dude, add a length of wire from your junk box so the probe will reach. Continuity will register on the meter whether digital or analog. WARNING: DO NOT attempt resistance measurements on a powered circuit. Power must be removed.

    Voltage: The negative probe goes to ground. Positive probe goes to the point under test. This test tells you THAT particular point has 12 volts. It doesn't tell you how it is getting there. It also tells you that the pont at which the negative probe is connected is GROUND. Like above, it does not tell you how it got there from the the battery. You either follow the wires from one end to the source of 12 volts and ground, or you use the the RESITANCE (continuity) checks to determine which wire is which if you can't trace them visually.

  10. #10
    Chief Petty Officer
    Join Date
    Sep 2010
    Posts
    630

    Default Re: Testing wires

    will try, I drew up the wiring but can't get the picture uploaded due to system changes??

  11. #11
    Chief Petty Officer
    Join Date
    Sep 2010
    Posts
    630

    Default Re: Testing wires

    Quote Originally Posted by Silvertip View Post
    Voltage: The negative probe goes to ground. Positive probe goes to the point under test. This test tells you THAT particular point has 12 volts. It doesn't tell you how it is getting there. It also tells you that the pont at which the negative probe is connected is GROUND. Like above, it does not tell you how it got there from the the battery. You either follow the wires from one end to the source of 12 volts and ground, or you use the the RESITANCE (continuity) checks to determine which wire is which if you can't trace them visually.
    If I am trying to isolate which black wire, and I have the one end at the helm, under the resistance test, doesn't the opposite end need to be attached, to say the negative post, or just test both ends of each wire? In other words, If I had a length of wire open on both ends, just put one probe on side A and the other on side B, and the meter will tell it is continuous?

  12. #12
    Vice Admiral LippCJ7's Avatar
    Join Date
    Sep 2010
    Location
    Douglas County, Colorado
    Posts
    5,298

    Default Re: Testing wires

    You can start by testing to the battery negative post but your going to need to disconnect the wires connected to the negative post to isolate the wire your trying to identify, your looking for the lowest number of ohms possible, some DVM's have an audible alert on the diode function that you can use to identify wires when your alone just hook up to both ends and listen for the beep, but if your testing continuity you want a value to tell you if not only this is the wire your looking for but also that the wire is in good electrical condition.

    Make sure your skin is not touching the probe leads metal surfaces it will not hurt you but it will read the resistance in your body and possibly mess up your readings
    2000 Crownline 248 BR
    454 MPI Bravo III
    "Wet Lipps II"
    2006 Dodge CTD 3500 4X4 Bighorn Edition

  13. #13
    Supreme Mariner Silvertip's Avatar
    Join Date
    Sep 2003
    Location
    Midwest
    Posts
    25,770

    Default Re: Testing wires

    When using the RESISTANCE (ohms) method for testing continuity of a wire the battery inside the meter provides the power which is why you ALWAYS work in this mode with power OFF and one end of the wire disconnected. Yes -- this is an end-to-end test of a given wire so you simply touch each end. As I said before, one end or the other needs to be disconnected so there is nothing else in the circuit.

  14. #14
    Chief Petty Officer
    Join Date
    Sep 2010
    Posts
    630

    Default Re: Testing wires

    Thanks Silvertip, yes, I figured I would have to attach extension wires to the probes.

    So I did a basic test for OHM on a small piece of wire. Zero when in contact, and some other value when one probe removed.

    Going to start on the two panel wires first. The main red should(or better) relate to the one by the battery that runs through the 15 amp breaker.

    Question though. When I test the black main ground at the panel, and place the other probe on what I believe may be the end run of a junctioning of accessory grounds, and I get a ZERO reading, could that be a reliable conclusion to move forward, or does the conjunction of several black wires tied into one that will eventually get attached to the NEG later on have flaws? Or is this splicing just "in lieu of" using a ground bus in the rear of the boat?

    Using this device, will it work on my mystery wires? If I have the visible end of a wire, what method would you use with it to find where it terminates, or leads to if they get lost in some cabled run?

  15. #15
    Supreme Mariner Silvertip's Avatar
    Join Date
    Sep 2003
    Location
    Midwest
    Posts
    25,770

    Default Re: Testing wires

    As I said before -- a resistance check is POINT-TO-POINT. If measures the continuity of the wire or the resistance of an object that is located BETWEEN the two probes. It cannot measure anything beyond either probe. Splicing is the same thing as having two, three, or a hundred wires all attached at a buss bar. A buss bar is equivalent to a piece of wire, a glob of solder, a crimp connection, or any other way of attaching group of wires to each other.

    If you don't now where one end of a wire terminates, you also have no idea if there is anything connected along a wire you want to test so you need to be very methodical in your testing. Current needs to flow from the battery, to an accessory, and back over a ground connection to the battery. If there are branches feeding other things or grounding other things you need to identify those. The meter or test light cannot identify those for you. It can only prove or disprove what you know exists.

    You don't need the meter to determine if the helm is getting power from the red wire attached at the battery. Disconnect it and if power goes away from accessories, the answer is yes. If they continue to operate, that wire is not the +12 volt supply. Since you KNOW (or at least reasonably certain) this is the case, why not disconnect the ground at the helm and simply run a new ground back to the battery so the existing red and new black wire are the feed and return. Problem solved, no meter or test light indicated. The existing ground for all accessories being run through the engine harness is simply a bad idea.

  16. #16
    Chief Petty Officer
    Join Date
    Sep 2010
    Posts
    630

    Default Re: Testing wires

    The ground test will determine that it is or is not part of the engine harness. My guess it is not, wish I could post the crude schematic I did of the current wiring, but this new format took away all of our albums, which is where I upload pics.

    Be assured, my panel ground when finished will NOT be part of the engine ground/harness.

    Thanks

  17. #17
    Chief Petty Officer
    Join Date
    Sep 2010
    Posts
    630

    Default Re: Testing wires

    Thanks Silver for the guidance, here are some resistance results.

    The red at the panel and the red at the battery that runs thru the 15 amp breaker lit up the multimeter versus to a number at zero or below. New there was activity, but it dawned on me that the breaker is something the wire is attached to, so I tested the other red coming out of the breaker, and zero, so the hot panel feed is confirmed.

    The 2 goofy wires that are pigged together, purple and white with green stripe are this. The pinkish wire at the panel was thought to be the sender, but it ain't. I tested that wire with one of the three in the group tied at the battery, the purple one, and they are continuous zero, or in other words, and additional hot feed to the panel. WHY? The only thing I can think for that is IGN power, but that won't be confirmed until I hook up the battery and test for voltage. I may consider a key turn test first. If this run is a redundancy, I will tie it off.

    The 3rd wire in that group is the white with green stripe, at the battery, and also in a harness leading into the fuel tank. I unclipped the harness and tested those ends, and ZERO, meaning the person wiring the gas tank ran a hot feed to it? That will be eliminated and the fuel gauge will be wired according to the diagram posted by you.

    Tha's the good news. I tested every black wire, and the goofy blue one that was once attached to the fuel tank harness and NEG post. Not one test to the black at the panel moved the readout from the number 1.00.........................

    Any ideas where to trace the panel ground to? I know I can ground the fuel tank directly, and I can splice the grounds for the bilge and anchor light and bus them aft and run a fresh ground from battery to panel, but just wondering what that answer could be?

  18. #18
    Supreme Mariner Silvertip's Avatar
    Join Date
    Sep 2003
    Location
    Midwest
    Posts
    25,770

    Default Re: Testing wires

    Every gauge on the instrument panel has a ground connection and that ground is merely jumpered from one gauge to the next. It is typically wired into the engine harness ground so the gauges come alive when the key is turned on. If you find two grounds on the ground connection on one of the gauges that is probably the phantom ground you are looking for. If not, neither I nor the meter can tell you "where" the panel ground comes from without some searching on your part. The meter can "verify" but it cannot "seek out" without help from you.

    Accessories other than gauges are typically grounded at the ground buss on the fuse/breaker panel which as I mentioned is a separate black wire running from the buss back to the battery. Hence the terms "boat harness" and "engine harness".

    Speaking of breakers -- when you measure resistance, having a switch or breaker in the circuit is not a problem since they are simply the same thing as a break in a wire. Turning off a switch "opens" the circuit and turning it on "closes" the circuit. Same for a breaker. To test them, disconnect one terminal and simple put the probes across the terminals. On = cclosed = continuity = good and off = open = no continuity = good. No continuity with a switch turned on means the switch is bad.

  19. #19
    Chief Petty Officer
    Join Date
    Sep 2010
    Posts
    630

    Default Re: Testing wires

    Silver, let me clarify a few things before the project moves forward.

    The boat was purchased from another State, and I had it shipped. In other words, it is a rehab.

    When I first brought it home, the battery was disconnected sitting next to a mess of wires.

    The first order of business was to hook up the reds and blacks. A friend did that while I prepared
    for an engine test and trim test. I have no idea if he attached the goofy color wires at the time to the battery.

    The ignition worked, started the engine, and the trim worked.

    While the battery was connected, we tested the bilge, it worked from the switch, horn peeped, lights worked. Therefore, at the time, the panel switches had a ground via whatever black on the battery provided. That is the main issue.

    As far as gauges, fuel never worked, and the speedo is pitot.

    Now on the continuity test I did on the black wire at the panel that obviously worked as the panel ground, if as it heads back to the rear and is junctioned with bilge black, anchor black, fuel tank black, and then ASSUME spliced into the engine ground, would testing the OHMS like I did give me the reading of 1.00 I got because of all the breaks, or splices? In other words, the panel black opposite end is NOT the wire I tested for continuity. I tested one end with the end of a different black wire, being the main engine black ground.

    Even though they(panel black and engine black) probably are physically connected to make the circuit, two unidentical wire ends should give me a 1.00, correct?

    If this is how it is wired, then the engine ground is my panel ground at this time.If all this is correct, then your advice was to ground gauge to engine and panel to battery NEG direct(boat harness).

    If this is the current setup, would doing the following make it right:

    Unravel and unhook the bilge, anchor light, and fuel tank grounds from the mess of junctions in the rear of the boat, while also the same with the bow light which junctions in the gunwale.

    Use the current black wire at the panel to ground the fuel gauge ONLY. Or not use it at all.

    Tie the bow light ground into my new panel NEG BUS. Tie the 3 rear grounds(bilge-tank-anc) to a rear NEG Bus. Run a new black wire off the battery to that rear Bus with a jumper feed, then continue the new black wire to the panel as my main ground, attach to the panel NEG Bus, and work off that for all the switches?

    Keep in mind I purchased a pre-wired switch panel from EZ so that part is done and paid for.

    Once I get this grounding thing fixed, then I can figure out what the rest is by more testing and the process of elimination.

  20. #20
    Supreme Mariner Silvertip's Avatar
    Join Date
    Sep 2003
    Location
    Midwest
    Posts
    25,770

    Default Re: Testing wires

    First, I understand what you are dealing with. Next, there is no reason to run a bunch of grounds from the front of the boat to the back. That's why you have a ground buss up front. Yes -- if you have a bunch of accessory grounds tied together and then that bunch is tied to the engine block, measuring any one of those wires will produce continuity. Again, you SHOULD NOT have accessory grounds going through the engine harness because that ground is "generally" not large enough to serve as a ground buss. In my view you need to obtain the wiring diagram for your engine. Without it you are wasting your time trying to guess, measure, guess some more and in the end you wind up frustrated, still have a rats nest, and as such an unreliable system. I will try one more time to explain what you SHOULD have. What you actually have is unknown since I can't see your boat. By the way, even a speedo has a ground connection as one is required to operate the internal light. Here are a few diagrams that illustrate how recreational boats are generally wired.

    Here is a example of what the BOAT HARNESS should look like. The two wires from the battery are #8 or #10 wire as they feed the fuse/breaker panel. If you have a pre-wired switch panel it should be connected here. If you have a pre-wired switch panel that contains fuses AND a ground buss, that replaces the fuse panel in the diagram. One accessory circuit is shown.

    [/IMG]http://i61.photobucket.com/albums/h51/40oldtimer19/Electrics/Basicwiring.jpg[/IMG]

    This diagram illustrates the instrument panel wiring (color codes are not standard). They are what they are for visibility only. Note that the switches in the diagram are powered from the boat harness but the instruments are powered from the engine harness. Although I show the instrument grounds going through the boat harness, they should go back through the engine harness for reasons we've discussed before. The various sender circuits are also in the engine harness.



    I guess the simplest way to explain the ground system is to have you ignore ANY accessories (including the fuel tank ground) that might be grounded at the battery (ignore those on the engine as well). With this in mind, there should only be four wires attached to the battery. Red & Black large cables going to the engine. #8 or #10 red & black going forward to the fuse/breaker panel. A circuit breaker should be within six inches of the positive battery post.

  21. #21
    Chief Petty Officer
    Join Date
    Sep 2010
    Posts
    630

    Default Re: Testing wires

    Not going to run a bunch of grounds. There are existing wires.

    Wish I could send you the schematic I drew up.

    I have ONE black wire at the panel, and it worked before as mentioned. It may be tied into the engine ground, a nono as you said, but I suppose it worked for 30 years.

    That said, a black comes from the bow light along with the gray, the gray enters the harness, the black stays in the cabled sheathing and probably splices into the black leading into the panel from the harness.

    The horn has 2 wires, red and black hanging freely, the red for the switch and the black to the BUS NEG

    No wires from these 2 items go to the back of the boat.

    At this point, the main black under sheath must run to the rear, and joins with the bilge/anc/tank grounds, and the guess is to the engine black somewhere under sheath.

    I will PM you with my email. If you email me, I will send you what I think is going on.

    I understand all that you are saying.

  22. #22
    Chief Petty Officer
    Join Date
    Sep 2010
    Posts
    630

    Default Re: Testing wires

    OK Silver, did more testing and visuals, and guess what, I misinformed.

    I found the panel ground. It is back there in a faded periwinkel, the purple wire I was mentioning. The meter did its job. I also traced the pink sender, and also determined I have no switch(IGN) power at the helm for the fuel gauge. Instead of tapping into the control box, I am just going to add a switch and use the panel feed.

    I also disconnected the harness at the fuel tank, and tested the ground there and the panel ground, and they are tied together which is correct.

    This leaves one more issue, more of a question.

    In this harness from the fuel tank, this is what it looks like:

    The harness clip on the tank side has 2 male and one female connections. The pink sender and the sender ground are the males. The female is a blue wire that has a connector ring.

    On the opposite clip are 2 females and one male. The 2 females accept the pink and black, and both have been traced and AOK. The male, which lines up with the blue female changes to a white wire with green stripe and appears at the battery. Testing for continuity concluded the following:

    Putting the probe on the white wire with green stripe at the battery shows continuity with the blue wire on the opposite end of the harness. I think this blue wire is the tank filler ground(bond) as it has a ring connector and is unattached. I am starting to think that the white with green stripe goes to the NEG battery post and the blue somewhere to bond the filler cap/tank? The cap and tank are metal.

    So the question is this. If I attach the white with green stripe to the NEG post, where do I attach the opposite end blue wire? They have continuity.

  23. #23
    Supreme Mariner Silvertip's Avatar
    Join Date
    Sep 2003
    Location
    Midwest
    Posts
    25,770

    Default Re: Testing wires

    You said you had my fuel gauge diagram. It is correct so Pink and black do not go together. Pink is the sender wire. It should have a ring terminal and attaches to the threaded terminal on the fuel sender. The other end of that wire ends at the "S" terminal on the gauge. The metal shell of the sender assemblyAND the filler neck, AND the tank itself must be grounded to Battery Negative. How that gets accomplished doesn't matter as long as the connection is made. Ideally, this would be separate connections (three wires) connected to the battery (also known as a star connection). They could also be daisy chained (neck to tank, sender shell to tank, and tank to negative post with one wire). There is no reason to add a switch to simply operate a fuel gauge. If the engine is an outboard, and the ignition switch is bad replace it as it will need to be fixed anyway. With the key on, check voltage at the "A" (accessory) terminal. 12 volts = good. No volts = bad feed to the switch ("B" terminal) or bad switch. If this is an I/O, check for voltage into the switch. With key on, there shoule be 12 volts on the "I" (ignition) terminal. It is that terminal that feeds the gauges as well as the ignition circuit back to the engine.

  24. #24
    Chief Petty Officer
    Join Date
    Sep 2010
    Posts
    630

    Default Re: Testing wires

    There are NO wires from the control box to the panel. There are no wires from IGN to the panel.

    All wires at the helm panel are present and accounted for. This boat originally had NO instrumentation except the pitot speedo which was lit from the bow light feed.

    The PO changed from the plastic tanks to a permanent tank so there was never a need from original to have an IGN feed at the helm. The Merc O/B controls do provide a plug-in and I suppose I could get one for a 1979, but for $6 I can add a switch, hence the reasoning.

    The PO stated he could never get the aftermarket fuel gauge to work, and I can see why. This gauge has only 3 connections plus the backlight bulb which has two prongs, one hot and one ground. The 3 gauge connections are S-I-G

    I will put the pink on S, the black is incorporated in the panel ground from the rear, so I will jump a black from G to the Bus to complete that ground, and for power, will get a switch from EZ and feed the I from it. Oddly enough, I have seen boats use switches for multi-tank reads.

    On the tip of the sending unit on the tank is a black jumper which goes to a post on the tank and secured, and tied to another black coming off and tests showed the tank and sender are grounded to the battery. The blue(maybe was green 30 years ago) shows a continuous read to the white with green stripe at the battery. I believe this was grounded via the NEG post of the battery, and the blue end(green) was once the filler bonding.

    Upon further inspection, one of the locknuts below the filler cap was almost off, the other 2 very tight. I believe this was how the filler cap was bonded, and when the new tank went in, they disregarded it. I attached the blue(green) to that bolt, tested the cap for a 1.00 between it and the wire at the battery box. I believe I just grounded the metal fill system for anti-static.

    So in a nutshell, there never was IGN power to the dash due to lack of instrumentation, no tach, no Voltmeter, nothing except a speedo pitot.

    As I mentioned, the boat has started, the IGN works, the key works all thru the engine harness. After using this meter, I learned from it and your help, and it is appreciated.

Similar Threads

  1. Spark? Compression? Remote starter? Testing coils? Testing power pack?
    By richardbrown67 in forum Johnson & Evinrude Outboards
    Replies: 4
    Last Post: November 20th, 2010, 08:49 AM
  2. 86 Mercruiser 350 Tilt and trim wires 2 wires coming from stern
    By No show in forum Mercruiser I/O & Inboard Engines & Outdrives
    Replies: 14
    Last Post: June 2nd, 2009, 11:20 PM
  3. spark testing and spark strength testing
    By pcrussell50 in forum Johnson & Evinrude Outboards
    Replies: 1
    Last Post: March 25th, 2009, 02:07 PM
  4. core spark plug wires for boats vs regular auto spark plug wires
    By coolguy147 in forum Non-Repair Outboard Discussions
    Replies: 5
    Last Post: October 20th, 2008, 09:10 AM
  5. testing 1..2..3..testing....1989 force 125
    By shawka0000541 in forum Force & Chrysler Outboards
    Replies: 2
    Last Post: July 21st, 2006, 08:49 AM
  1. iboats Forum Directory - Over 100,000 forum posts organized by topic