So as far as the voltage jumps it turned out to be a bad alternator. I went and exchanged it because the internal regulator was bad. Now the alternator is putting out the correct voltage but my voltage gauge is still acting up. I have cleaned each connection and used dielectric grease on the pins. I have also taken the gauge cluster out and cleaned all contact areas for the voltage gauge. I put it all back together and at first without anything on the gauge reads 14v but after I turn on the head lights, aux electric fan, and the KC's on and then turn them all off, the voltage stays somewhere around 12-13 and doesn't really recover. When the voltage at the battery posts recover to the normal 14.2 or 14.5 Does anyone know of any tests I can do to the voltage gauge to make sure its working correctly? I'm probably going to go through the wires again and make sure there are no shorts, maybe double check all the connections again to make sure I didn't miss anything. I'm kinda stumped on this one, but don't want to buy anther gauge cluster if that's not the problem.

 

My 90 does this still even with cruisers ground refreshing, new battery cables blower motor ect.... even with the drop in voltage it's never dropped below 11.8 volts even with the headlights and blower on.

 

Ya, I just got done doing the mod to improve the ground for the gauge cluster by making a jumper wire. I turned everything on and Im still having issues. with my head lights on, KC's on, aux electric fan on, and AC this is what my gauge inside the XJ reads.



Outside though at the battery its 14.2 v Then when I turned everything off and its just idling this is what it went back too.



and the battery posts read 14.5 or 14.7 So at this point Im kinda stumped. Im debating on pulling another voltage gauge from the junk yard, but whats to say that one isnt having problems either.

 

looking like 12 volts to the gauge, it's a positive lead thing now that you have me thinking about it. But then again it could end up being a ghost chase.

 

What do you mean by a positive lead thing? like the wiring from the alternator to the gauge?

 

Yeah something like that. If the system has drawn power before it gets to the gauge you will have a lower voltage reading, but really you don't.
It's like using welders on a slave set-up, the first one will always have full power but the second and third and so on will lose power as others strike an arc. If the gauge is last in line well...

 

Update: cruiser54 the jumper wire from the gauge cluster ground to a near by bolt did brighten my background lights of the cluster. I was driving home from work today and really noticed a difference. Just thought Id let you know about that.

 

Ok now yall are where im at on this .Mine used to read high at all time . Im thinking its gotta be the gauge just worn out .They can be replaced individualy .But like stated above who saying another ones gonna be good .

 

Ok found so called fix here....http://www.jeepforum.com/forum/f11/r...ge-fix-684375/

 

Thanks for the update. I noticed that also.

 

I read that a coupla years ago.

But when I upgraded my battery and alternator cables, the improvement was enough that I decided not to do it.

Check this out. Not only will your gauge read higher, your Jeep will start more quickly and handle higher electrical loads much better.


http://www.kelleyswip.com/electric.html

 

Ive all ready upgraded it did make a world off diference on everything but the gauge reading im gonna go run a fused jumper tooday or tomorrorw and see if it works b4 hard wireing it in.

 

Cool. Keep us informed.

You did add the ground wire already?

 

Yep did those over a year ago .

 

Should have clarified- the instrument panel ground.