Faria Temp Gauge not working

mikegmi2

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Greetings, first post, and wanted to first say thanks for this message board as I have spent 2 days reading old posts and learning about my problem, which I believe I almost have figured out due to all the great info here...but still have a couple questions.

First, my boat is a 2007 Kayot Z201 with a Merc 5.0L MCM (serial 0W672003). I have 6 Faria gauges on my panel, speedo, tach, temp, oil, volt, trim. Other than the depth sounder beeping pretty much every time I put the boat in the water, and having to push the Mode button to turn it off, all the other gauges work fine, except the Temp gauge. It never moves and always stays at 0.

My first clue that the gauge was probably dead was than when I turned the ignition to ON (not crank), all the other gauges 'jump' a little (except speedo and tach because I believe those are mechanically controlled?), except the Temp, it never moves.

So i unhooked the sending unit tan wire, turned the ignition to ON (loud constant beep) and tried grounding the tan wire to some bare metal on the engine, gauge doesnt move.

I then checked the resistance from the side body of the sending unit to the engine, and its pretty much 0ohm...next I checked resistance from engine to tip of sending unit, and I get basically around 100ohms...I have a very cheap multimeter so when I touch the tip of the sending unit it shows me 100ohms for a couple seconds, then goes back to 0, then if I lift off and touch again, it shows 110ohms, or 115ohms, and back to 0 again, and I can do this over and over but it is usually around 100ohms.

Finally I checked to see if I was getting 12V to the gauge by checking voltage at the wire harness that plugs into the temp gauge, and I got 12.3V.

So I believe I can conclude the gauge is bad, but I have a couple questions...

Here is a pic of the harness that plugs into my temp gauge:


- As you can see, there is a black, blue, and purple wire. I'm guessing one is ground, one is 12V, and one is for teh sending unit signal?

But in this pic, the sending unit wire is clearly tan:


I can't follow the tan wire because it immediately goes into a black wire protective sleeve that contains a handfull of wires, and basically stays within this sleeve, which then joins into a larger sleeve, so there's no chance I could trace excetly where it goes unless I ripped everything apart, and that would take forever.

So my question is, is it common for this tan sending unit signal wire to splice up with either the blue or purple wire that is on my temp gauge wire harness? I figure it must, otherwise how else would the sending unit signal get to the gauge?

Also there are 4 pins on the gauge, but only 3 wires going into the harness. Maybe the sending unit wire got cut or pulled out of the harness? But I dont think so, because these gauges only need 3 inputs, right?

Here is a pic of the back of the non-working temp gauge:


The gauge is Faria part number GPC067A, which is located on the side of the gauge, on a sticker label.

One other problem is, Faira told me they no longer make this gauge, so I would have to find something compatible...but everything I have looked at does not have a pinout on the back that matches my harness...so I would have to cut the harness and manually wire it to the back of any new gauge I got...but I dont think that would be too difficult.

Any help or comments regarding my question about why there is no TAN wire going into the harness for the temp gauge (or any other comments) are greatly appreciated.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: Faria Temp Gauge not working

Sounds like you've pretty much narrowed the gauge down as being faulty.

The tan wire on the engine sender is the standard colour Merc (and most of the boating industry) for temperature gauge, so at the engine end it's correct. That wire will go into the engine harness connector (big 10 pin black thing at the back of the engine, stb side) on pin #3. I've never seen those gauge connectors before (look kind of good!) so I suspect they are Faria specials, and that might also explain the lack of colour consistency. You should be able to run a continuity wire from the sender to the wire on the gauge connector to confirm you have the correct wire hooked to the gauge. You might also find that somewhere between the gauge connectors and the engine connector is another connector box, where the Faria harness and the Merc harness meet....

As for replacing the gauge. If Faria don't make that one or any like it with those Packard connectors on them, I guess you'll not have much choice but to chop the connector off and put lugs on...

Chris.......
 

Don S

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Re: Faria Temp Gauge not working

You're missing the tan wire to the gauge? There should be 4 wires in the harness plug for the gauge.
 

mikegmi2

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Re: Faria Temp Gauge not working

Really? I thought these gauges only needed 3 inputs? Power, ground, and signal from sending unit.

What are the 4 inputs then?

If that's true that the tan wire should be going into that harness as well, then that is obviously the problem, but I thought these Faria gauges only needed 3 inputs...
 

Don S

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Re: Faria Temp Gauge not working

Black is ground,
Blue is power to the light,
Purple is power to the gauge,
Tan is the one that goes to the sender.
 

mikegmi2

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Re: Faria Temp Gauge not working

Black is ground,
Blue is power to the light,
Purple is power to the gauge,
Tan is the one that goes to the sender.

Oh wow, well then what the...did someone purposely cut the sending unit wire going into this harness? Maybe it shorted out and burned off? I don't get it.

Actually now that I think about it, I don't think these gauges have lights (i could be wrong, I havent taken it out at night yet)...

Here's a better pic of the harness...could that be a burnt end of what used to be the tan wire going into the harness? It's like black, not tan:


Also here is the front of the gauge:
 

Don S

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Re: Faria Temp Gauge not working

Looks like a plug in that hole, not a burned/melted wire.
The problem is, the gauge is not Merc, so maybe Faria uses a different wiring setup.

I'm going to move this over to the electrical forum and see if someone there might have some more input.
 

Auger01

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Re: Faria Temp Gauge not working

I would check for continuity between the brown wire at the sender to any of the wires at the gauge plug to see if any of those are connected to the sender. If none are connected to the sender, I would run a jumper wire from the sender to the unused (fourth) pin on the gauge to see if it would work that way.
 

mikegmi2

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Re: Faria Temp Gauge not working

Thanks very much Don. I am hoping the conclusion is a bad gauge, and not some sort of wiring nightmare ahead of me.

Perhaps in the meantime I can order a new gauge...they're only $25 and I found one fairly close to what mine looks like...

This one has a 4 pin harness connection on the back, different than mine, but looks lamost the same:
Faria GPC606E Euro Series Boat Water Temperature Gauge | Great Lakes Skipper

And this one looks very similar too, but it has no harness connection on the back, only 3 brass pegs that im not sure if theyre for mounting purposes, or ground, sender signal, and power?
Faria GP4075A Boat Temperature Gauge | Great Lakes Skipper
 

mikegmi2

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Re: Faria Temp Gauge not working

I would check for continuity between the brown wire at the sender to any of the wires at the gauge plug to see if any of those are connected to the sender. If none are connected to the sender, I would run a jumper wire from the sender to the unused (fourth) pin on the gauge to see if it would work that way.

So, connect a jumper wire from the tan sender wire at the engine, to the 4 wire harness wires? What would I be looking for, as far as voltage, resistance, and what reading would tell me that the sender signal is properly being transfered to the wire harness (im not that great with this stuff). I would assume I would be looking for something like 100ohms to verify 'continuity'? Maybe im wrong. Thanks.
 

mikegmi2

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Re: Faria Temp Gauge not working

Here is a clearer photo of the wire harness for my temp gauge:


You can see from right to left, A is purple, B is blue, C is black, and D is not connected...has a plug.

Here is a schematic I got from Faira today:


Looking at the schematic, the D port can either be used for the gauge signal, or be NC "for daisy chained instruments only".

I don't understand that at all. How and why would the 'gauge signal' wire, of any gauge, be daisy chained? Doesn't daisy chained mean they're all hooked up together in series or parallel? Or am I misunderstanding something.

Anyhow this schematic helps, but also confuses further becasue MY temp gauge harness D port is clearly plugged on purpose, yet I don't understand how it would ever work...or how any gauge would ever work, without the gauge signal input wire?

Could they have accidentally shipped these wire harnesses on accident, rendering the temp gauges on all of these boats useless? Hard to believe that...
 

Don S

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Re: Faria Temp Gauge not working

Look at your oil pressure gauge and see what color the wires are. Blue can also be oil pressure. See if your oil pressure gauge has a tan wire on it...

To check continuity, go from the temps sender wire to (I would guess) the blue wire) in your harness. You should see near 0 ohms since the sender is what has the resistor in it.

Purple is ignition (12V), and black is ground.
 

Silvertip

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Re: Faria Temp Gauge not working

Stop with the jumpers, voltage, resistance checks and think about this. First, that plug has +12 volts, Light, and Ground connections. No tan temp sender wire. What does that mean? It means that it is not the plug that connects to a temp sender but rather the only gauge that does not require a sender which would be a VOLTMETER. So check the plug on the voltmeter to see if it has a tan wire. If it does, swap the two and go boating. The voltmeter would still work properly with the tan wire since it would not be connected internally on the gauge. If the plug on the voltmeter doesn't have a tan wire, look under the helm for another loose plug that does have a tan wire. The plug you are currently dealing with is obviously NOT one that would apply to a gauge with a sender. Boat harnesses are very generic so some extra plugs are generally included since the boat builder doesn't know what accessories/instruments will be ordered or added.

By the way, continuity on a wire with no connection on either end is "0" ohms or in other words, shows as a dead short. An open circuit is not "0" ohms, it is "infinity." And you never measure resistance on a circuit that is powered. The internal meter battery is used for resistance measurements.
 

Don S

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Re: Faria Temp Gauge not working

We were posting at the same time.

Your drawing proves the wire is missing. You could only daisy chain them if your engine had an ECM for digital gauges, and you have a carbed engine so we know that's not going to happen.

You have a loose tan wire behind the dash somewhere. Bet the oil pressure gauge has 4 wires to it.
 

mikegmi2

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Re: Faria Temp Gauge not working

Surprised I didn't think of that guys. I will go check all the other gauges, specifically the volt gauge or oil gauge and you're right, I hope there is an extra tan wire going to one of them.

I'm at work so I will report back what I find (i'm about to go back to our lab and test the gauge with a power supply, 100ohm resistor, and see if it moves the needle to half way), and thanks again.
 

mikegmi2

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Re: Faria Temp Gauge not working

The gauge works, I rigged it up as shown below, connected red to 12V, then touched the other end of the resistor to ground on the power supply and bingo, it moved to about half way (i think its a 101ohm resistor if I remember my color code numbers).


Next, checking to see if the wrong harness was plugged into this gauge...report back tomorrow.
 

achris

More fish than mountain goat
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27,468
Re: Faria Temp Gauge not working

Yes, that's a 100 ohm resistor (1/4W, carbon film)... The drawing you posted showing the wiring schedule proves that the wrong connector is plugged into the gauge. Someone suggested you check the other gauges to see if any have a tan wire in the 'D' position on the connector. I think that is a very good idea. If all the other gauges work correctly, then it's likely to be the voltmeter, as the connector you're holding looks like that where it belongs....

Chris..............
 

mikegmi2

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Re: Faria Temp Gauge not working

Bingo. Even though it was raining out, I went out to my driveway, climbed under my boat cover...and sure enough, the voltmeter had 4 wires going into its harness, including a tan one in port D.

Unplugged it, swapped with the one that was being used for the temp gauge, and turned ignition to on, and the needle jumped...so it's working now and I bet it works fine when I take it out on the water.

The bizarre thing is, I had to cut 5 old white, yellowing, zip ties to be able to move the harnesses from one side of the gauge panel to the other (the voltmeter and temp were on opposite sides). I mean it looks like this has been this way for years, maybe even was installed wrong from the factory?

I just bought the boat last week, everything worked great except the temp gauge, and previous owner said it never worked.

I even looked through all the service records that were inside the boat owners manual case he gave me with the boat, and one winterization receipt from 2011 had a comment listed on the bill - "See why temp gauge isn't working".

Thanks very much to everyone that helped me resolve this issue, especially Don and Silver. Much appreciated.
 

Silvertip

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Re: Faria Temp Gauge not working

Love it when a plan comes together!!!!!!!!! Pat on the back to you for fixing a problem that has likely never been thought of as a problem. Since the TEMP and OIL gauges are the most important gauges on the boat, one would think prior owners would want it working but apparently folks don't complain until the engine goes up in smoke. Idiot lights replaced gauges on cars years ago because few people understood what the gauges were telling them. Red idiot lights didn't help much because those same people thought they would get things looked at next week, next month or next year. The auto industry is moving back to gauges but at least there is now a message center that says "Fix Me Now!" and the vehicle goes into limp mode to entice the driver to head to the shop. .
 

NYBo

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Re: Faria Temp Gauge not working

And a pat on the back for Master Silvertip who nailed the diagnosis!:clap2::clap2::clap2:
 
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