teleflex voltmeter in dash wired wrong?

[rayaa3]

About a month ago I bought a new to me 2006 tahoe 215 outboard with an optimax 150.

I'm starting to think that at some point the previous boat owner let a monkey under the dash. There were a couple of small issues when I lake tested the boat - as it related to gauges and things on the dash...most seemed easy to figure out, so I bought the boat. After getting into it, some seem to relate to someone goofing around behind the dash. Or what seems impossible to me, that some things left the factory and never actually worked right.

Tachometer was set to 5P instead of 6P for a optimax, leading to reading higher than reality RPM...fixed
Horn didn't work - replaced - easy...fixed
Trolling motor onboard charging system didn't work, and trolling motor won't turn.
Charger had corroded inline fuses and the fuse holder basically disintigrated into my hands when I was trying to figure out why it wouldn't charge the batteries - had to resplice in new fuse holder inline, replace fuses...fixed.
Jumper wire between trolling motor batteries to make 24v series was torn from terminal...respliced new ring terminal on jumper...fixed.

So I'm feeling pretty good about myself...and thinking...ok, most of this is wear and tear stuff..little bit of moisure, vibration, stuff breaks. Kinda weird that the tach was set to 5P...wonder if it has always been wrong (it's a 12 year old boat, it's possible no one ever really paid attention to RPM not looking correct).

Then I start looking at the voltmeter...which doesn't move. The battery has juice, the alternator charges, The boat runs great. So I start digging around behind the dash. I'm neither a mechanic or electrician.

But what I'm finding makes me think this is wired wrong, If this is correct...

https://www.jamestowndistributors.com/userportal/document.do?docId=840

So if that is correct, and IF I am reading it correctly (and that's a big if), I have a problem with how I'm wired. Please read how I'm wired and confirm my understanding of what's wrong:

How I'm wired:
I have a -12V grey wire going to the blade connector for the light. That wire then continues to the Ignition terminal on the bottom half of the guage.

There is a terminal in the center of the back of the gauge according to every diagram I find that is suppose to be ground, On my wiring it's negative 12v, so that is correct. So the question is...is there a reason the I terminal and blade terminal for the light connector would have -12V wires on them? Shouldn't they be +12V?

There is a terminal across from the Ignition, which according to diagram linked above is sender (S) and not used on voltmeters...and on mine there is nothing on that terminal, just a red plastic cap. Is that really not used? Or Is this where +12V should be coming into the voltmeter?

I took this video earlier - before finding the diagram above. I *think* my problem is that the light and I terminal are suppose to be +12V, which complete the circuit with the ground in the center of the gauge. I think that's what I'm seeing in the diagram above.

However, because I am so far outside of my area of expertise I would appreciate any input. I did find a loose red blade connector behind the dash that is +12V hot and not going anywhere. (not connected to any switches or gauges). its' about a 12 gauge wire (again, I'm eyeballing this and don't do this for a living...I didn't see any labelling to how thick the wire was consider 12 gauge a guess). that could go to the blade connector on the light bulb, I would just need to add a jumper wire that goes to the I terminal. I like the idea that I'm finding the wire that originally went here...I can't find any other wires that are not already terminated some place.

Of course, if I take off this -12V grey wire I'm left with the question - where the hell did this -12V grey wire I'm pulling out of it originally go? Unless it has literally never worked from the factory (Tahoe boats have quality issues like this?) and no one ever had it fixed, it seems like this should go some place.

The only other electronics that don't work are the speakers (radio comes on but no sound) - I doubt that's related to this -12V wire

Fuel gauge gives me doubts...it's possible it's wired wrong too...haven't gotten there. So far it always reads full, but I haven't spent enough time on the boat to burn enough gas to doubt it.

Video of me showing how it's wired...
https://www.youtube.com/watch?v=8s1VVoEo1Nw

thanks for any input here.

 

[mikeyk101]

I am new to the boating world too and not an electrician but that doesnt sound right. When you say -12v, I am assuming you mean it's a ground wire and gray is definitely the wrong color for that. Ground should be black. The gray wire will normally be used for the Tachometer feed or for navigation lights. I just got done doing a bunch of rewiring including adding dash gauges and new wire for the navigation and anchor lights. I had a new harness that plugged into main wiring harness near the ignition switch that had a gray wire, purple wire and a black wire. The gray wire was for the tachometer feed. The purple wire was a switched 12v positive so power only ran through when switch was on and the black wire which was a ground. I used that harness and purple wire to attach to the 12v+ input on voltmeter and 12v+ input to tachometer. The ground was first attached to the tach ground , then daisy chained to the volt meter ground and then the speedometer ground. I also ran a dedicated fused 12v feed from battery to a new fuse panel I wired under dash. I also ran a dedicated ground from battery to ground bus bar also on the new fuse panel. I ran blue wire from the fuse panel to the nav light switch. I also ran gray wire from navi light switch to anchor light. On the other terminal of navi light switch, I ran a gray wire to bow navigation and a blue wire to tach light, and daisy chained to volt meter light, and finally to speedometer light. So now the dash lights only come on when the bow navigation light is on. I ran 16 gauge boat primary wire for all the dash and anchor/nav lights, I ran 10 gauge wiring from battery to new fuse panel. All connectors were heat shrink crimp connectors and I used a ratcheting crimping tool that I bought off Amazon which works the first time every time which amazed me. I also converted every bulb and anchor/navi lights to LEDS.

 

[Silvertip]

Regardless how it is wired now, a voltmeter needs only three connections. One for the internal light, one for the ground and one for +12 volts. Those are typically labeled +, -, and L. If the "S" terminal you mention is on the ignition switch, that is NOT a "sender" connection. That's the STARTER or SOLENOID terminal which energizes the starter when the key is turned to start. 12 volts and ground are wherever you find it. L is connected to +12 volts in some cases which means the dash lights are on any time the key is on. Normally the light connection would come from the NAV side of the NAV/ANC switch.

 

[rayaa3]

Thank you!
so I think I have several issues.

S is not connected, no prob there.

I, ground, and light are all connected to ground

I have work to do. Pretty sure the light is ground on all gauges(and does not work).

what do you call these terminals? need to order some or replace them with rings when I fix it.

 

[rayaa3]

They kind of look like a butt connector or female bullet but I've never seen either used like that

 

[mikeyk101]

I dont see any reason you couldn't use crimped ring terminals with heat shrink on them. I have the same studs coming out of my gauges and used ring terminals and an extra nut to hold them on.

As far as the light terminal, you may want to double check that. From what I have seen, it is usually a 12v positive coming from light switch that attaches to the light terminal on the gauge. The ground is usually a single ground wire that also will be used not only for the gauge but the gauge light. For example, the tach or volt meter needs a ground to work but doesnt need the gauge light. Usually there will then be a switched 12v positive feed that will be used to activate the gauge light circuit. It will share the ground that is already being used for the gauge to operate. Having 2 ground wires to any of the gauges doesnt seem to make much sense.

 

[mikeyk101]

Ground would be attached to center mounting stud. A 12v switched positive purple wire would be attached to the "I" which I am guessing is where the red sleeve is. That black wire in the front probably doesnt belong and should be unhooked. A blue 12v positive wire needs to be run from the light switch to the what looks like a spade terminal on the back side of the photo.

 

[mikeyk101]

The installation instructions seem pretty straightforward on the wiring as long as you can figure out which wire is which. Identifying and then using the proper wiring colors will be the key...

 

[rayaa3]

Well I've figured out my problem. My ignition wire on several of these gauges splice into a purple wire which is -12v. The more I dig in the more I wonder how any of this is working.

 

[rayaa3]

Ok, maybe im doing this wrong. The purple wire in question eventually splices with a purple wire off the ignition/key switch. When would this energize with +12v? Would the engine need to be running or merely key inserted and turned to run?

 

[rayaa3]

Ok... got past a little of my own stupidity. Put key in run and all these wires on I suddenly energize +12v.

Laugh if you need to.

 

[GA_Boater]

gauges splice into a purple wire which is -12v

Reverse your meter leads when you see a -12 volts. There ain't -12 volts anywhere. I'll join in your laughter. :rofl:

Go boating or sit behind the wheel and make motor sounds. :smile: