Backlight on Tach stay on??

[dspencer]

I need help, how do you get the back light turned off on the Mercury/VDO Tach #79859020? Even after turning the battery switch off the back light stays on. The boat is a 2000 BW Ventura with a 135 Optimax.
thnx

 

[roscoe]

Re: Backlight on Tach stay on??

Well, since we can't see the wiring from here, it is hard to be specific.
But obviously, the wiring is not as it should be.

I would go through the entire wiring system and look for any abnormalities.

As a temporary fix, try removing all wires from the tach, except the signal wire and the ground wire.

 

[ricksrster]

Re: Backlight on Tach stay on??

Try wiring the tach light wire to the other instrument lights' wiring or the navigation lights.

 

[WillyBWright]

Re: Backlight on Tach stay on??

Disconnect all spliced-in gadgets and wire them separately from any wiring that has anything to do with the motor and gauges. I'm absolutely appalled by some wiring jobs I see when stereos and locators are installed by the inexperienced. The boat and motor circuits are separate to a degree, and many times the addition of gadgets compromises the separation if not done correctly. Out of sheer guesswork, I'd bet that you have a stereo with a memory that needs power all the time. Somehow that is backfeeding to the tach light.

 

[dspencer]

Re: Backlight on Tach stay on??

THNX just fixed it

 

[Boatin Bob]

Re: Backlight on Tach stay on??

That's nice but what was the fix?? I thought these boards were for sharing information??

 

[dspencer]

Re: Backlight on Tach stay on??

Just unplugging the Mercury harness conector to the back of the gauge reset the backlight and the mode button started to respond to I think this system is a
SC1000 SMART CRAFT. Who knows why the light stayed on I wish I could give a better explanation but thats all it took.