The tachometer worked last summer...

[zsr22]

A little history... My 2003 Crownline 210 BR (Mercruiser 5.0 MPI) was broken into over the winter and the thief ripped out the CD player. The CD player was replaced and all is well in that department. However, upon getting the boat ready for the summer I noticed the tachometer no longer works. The digital hour display at the bottom of the tachometer works but the needle doesn't budge. Also, the illumination light doesn't work on the tachometer gauge either. The rest of my gauges light up at night and function properly but the tachometer is dark.

I've stuck my head up under the dash and everything still seems connected. Any ideas?

 

[Philster]

Re: The tachometer worked last summer...

For the tach:

You need a blue wire for lighting.
You need a gray wire for the signal from the engine
You need a purple wire for power.
You need a black wire for the ground.

Here is the likely issue:

You might see all these wires properly connected to the tach. However, they (except for the gray wire) are connected to some other point such as another gauges terminal screw.

I would focus on the purple wire first. That's the key-on power. If it is connected, then see where it comes from (and goes to). It likely connected to take power from one location and feed power to another. It is a link in a chain. It might be the last link, so that could explain why all the others are working.

Since the digital part works, I suspect the tach has key-on juice (purple), but the signal (gray) is missing, along with the lighting (blue).

Use an electrical tester. Get one. Take 30 seconds to learn how to use it and save yourself grief. Or, really study the wiring to see how each wire jumps from gauge to gauge.

Blue is lighting for all gauges. Purple is power for all. Black is ground for all. Gray is unique to tach (signal from engine).

 

[jtmarten]

Re: The tachometer worked last summer...

If it's a Faria, I wouldn't be suprised if it just failed. I had a Faria tach w/digital hr meter, had to be sent back to Faria twice for replacement for the same issue. After it failed again, I just replaced it with another tach and never had any other issues.

 

[zsr22]

Re: The tachometer worked last summer...

The tach is, in fact, a Faria. And while messing around with it, the illumination started working. I get ~6v from the gray wire going into the tachometer when the engine is idling. Anything else I should check or just chalk the tachometer up as being bad?

Thanks.

 

[Philster]

Re: The tachometer worked last summer...

Get yourself a new tach.