navigation lights cause temp gage to read hot/red zone

[TeamSmith]

We took our boat to the shop because the temp gage reads in the red zone if we turn on the navigation lights. The boat mechanic ran tests and said the boat is not really running hot, so he thought it was a faulty instrument panel. He claims he checked the wiring, and that the wiring looks fine. I don't see how that can be. The navigation lights should have nothing to do with the temp gage.
Anyway, he said he does not work on instrument panels, so we should take it to the Regal Dealer.
I should have mentioned that....it's a 2001 21 ft Regal Bowrider....5.0 Volvo Penta I/O engine.

Any ideas before we take it into the dealer? Does it sound like a wiring issue to you?

 

[seabob4]

Re: navigation lights cause temp gage to read hot/red zone

Your gauges get their power and ground from the engine harness. The nav lights get their's from the boat harness. The common point is the ground. Check all your grounds at the ground bus bars, and the batts, make sure they are tight and in good condition.

 

[Lyle29464]

Re: navigation lights cause temp gage to read hot/red zone

sounds like the ground is weak. I would run a temporary ground wire from the battery to the ground wire on the back of your gauge. If that fixes it just clean up the ground wires on the back side of your panel and the buss bar that has the ground wires on it.

If the ground wire did not help. take it off both terminals and put it on the + side of the battery and the B post on your guage and try that. If that does it just clean up the postive side of your buss bar and wires running to lights gauges etc.


oops I was typing while sea posted. ( do what he says)

 

[seabob4]

Re: navigation lights cause temp gage to read hot/red zone

sounds like the ground is weak. I would run a temporary ground wire from the battery to the ground wire on the back of your gauge. If that fixes it just clean up the ground wires on the back side of your panel and the buss bar that has the ground wires on it.

If the ground wire did not help. take it off both terminals and put it on the + side of the battery and the B post on your guage and try that. If that does it just clean up the postive side of your buss bar and wires running to lights gauges etc.


oops I was typing while sea posted. ( do what he says)

I like I/Bs too. Big Rudders and big props, got to get that steerage way going...

 

[focker1636]

Re: navigation lights cause temp gage to read hot/red zone

I have the exact same issue. Turn on the nav light and the temp gauge spikes, turn them off and the temp goes back to normal immediately. I understand it's some ground issue when the instrument panel light engages, as the nav lights control the panel lights.

My instrument gauges are part of a circuit board cluster, with no individial wiring for each gauge.

Let me know what you find to the root cause.

 

[Silvertip]

Re: navigation lights cause temp gage to read hot/red zone

There is another post on this topic in the Boat forum. Same deal. Read what I have to say there.

 

[focker1636]

Re: navigation lights cause temp gage to read hot/red zone

TeamSmith, you don't happen to have a 1999-2002 Bayliner do you?

I do (2001 Bayliner 215) and I found a post on a Bayliner owners forum where the exact same issue was reported and tracked down to a faulty series of dash panels made by VDO. Apparently there is a problem where the cluster is very sensitive to increases in voltage, resulting in this problem. He was able to get a part from VDO to resolve the issue. Here's the post, including VDO contact info:

http://www.baylinerownersclub.org/forum/showthread.php?t=47259

 

[jhebert]

Re: navigation lights cause temp gage to read hot/red zone

The problem lies with the ground path on the temperature gauge.

 

[TeamSmith]

Re: navigation lights cause temp gage to read hot/red zone

Thanks everyone. Will check the ground path. As of yesterday, the speedometer also quit working. And I will correct what I originally said....it's the docking lights that are causing the temp gage to read hot....not nav. lights.

 

[jhebert]

Re: navigation lights cause temp gage to read hot/red zone

Thanks everyone. Will check the ground path. As of yesterday, the speedometer also quit working. And I will correct what I originally said....it's the docking lights that are causing the temp gage to read hot....not nav. lights.

I don't know exactly what qualifies as "docking lights" but I imagine the lamps probably draw a lot of current. When you switch on those lamps, the heavy current draw causes a voltage drop in the power distribution feeding the secondary power distribution panel. This may be affecting the temperature gauge reading. This is especially likely if the temperature gauge sender unit is threaded into the engine block, and it is getting its ground reference voltage from there.