Bench testing a gauge cluster/tachometer?

[Airborne Janitor]

Is it possible to "bench test" a renix gauge cluster? I'm really concerned with the tachometer. I did a full cluster swap in my MJ and the tach "sticks", it sort of works, sort of doesn't. I'd like to be able to test the cluster I just picked up from the junkyard before swapping it. Thanks.

[eaglescout526]

What year is the tach? It can be tested, you need ground, power and a wire lead to the coil or the tach signal from the diag port. 

[Airborne Janitor]

I want to say the junkyard tach is either an 88 or 89. It's renix for sure, manual speedo cable and it's blue. 

[eaglescout526]

Blue faces or the black “sport” style?

 

Ok that doesn’t really matter but you should still be able to test it. 

[Airborne Janitor]

2 hours ago, eaglescout526 said:

Blue faces or the black “sport” style?

 

Ok that doesn’t really matter but you should still be able to test it. 

 

Black sport style. Is there a wiring diagram of sorts showing how to test it?

[eaglescout526]

Ummmmm there might be a wiring diagram that I can find right quick.

[eaglescout526]

 

From the 88 XJ electrical manual. 

[Airborne Janitor]

You reminded me that I actually have the 89 FSM. I was able to dig up the correct wiring diagrams and test the junkyard tach from the diagnostic port. Unfortunately it didnt work.