Bad Gauge cluster or grounds? Electrical demon

Hell everyone! On my third XJ here. It's a 1994 4.0/aw3/231 with power windows and locks.

I'm used to no gas or speedometer gauge on my last Cherokee. But I want everything in check with this one. I'm sure it is simple. The other day at the u pull it I had the option of a gauge cluster or a small window to fix the rear passenger door window. So I went with the window and fixed the glass today.

I did pull my cluster and clean the contacts on the back. The lights work on the dashboard and the water temp gauge is operational. However it does not drop down below middle and will randomly fluctuate higher when I am driving. I don't think it's a thermostat. Jeep does not overheat or smell at all. Just odd that the one gauge is kind of working and others are not.

Tomorrow I'm going to check all fuses over. I want to check all grounds as well. Can anyone tell me where each ground is generally located so I can go right to those points? The stereo is powered by a wire I need to attach on the ground. I don't know if it was done ghetto like that because of an electrical issue that is not powering the radio. But everything else works fine.

One more little gremlin is with the power windows. Right rear door does not roll down. When I changed the window today I put power right to the window motor so I could change it out. But there is no power getting to that switch. Nobody can roll down there window. I'm thinking the relay for my unlock switch may be bad. Is that located right behind the panel? People are capable of "stopping" me from rolling down there window. Telling me it could just be the relay for that switch. I been trying to find a diagram because I'd like to find out why the rear right door is not getting power.

Thanks for your time :]

This applies up to 1990, but it COULD be the same for your Jeep. You'll have to look up under the dash.

Improving the Instrument Panel Ground
The ground point for the complete instrument cluster on your XJ or MJ is located up under the driver’s side dash. If you lay on your back and look up under there with a flashlight, without wearing a hat, you will see a black wire attached to a shiny piece of metal almost directly above the hood release knob. The screw will have either a ¼" or 5/16" head on it.
This ground point is responsible for handling the ground circuit for the following items: Dome lamps, Seatbelt and key warning, trans comfort switch, wiper switch, headlamp switch and delay module, fog lamp switch, cargo lamp switch, all instrument panel grounds and illumination, power windows and door locks, cruise control dump valve, and a few more things.
The problem is that where the ground point is located does not have a good contact with the chassis where the ground should be. The solution is simple.
Make up a jumper wire with #10 gauge wire about 10" long. On one end, crimp on a ¼" round wire terminal. On the other end, crimp on a 3/8" round wire terminal.
Remove the screw from the existing ground wire and attach the small terminal of your jumper so that the original wire and your new jumper share the same attaching point, one over the other.
Look above the driver’s side plastic kick panel just forward of the top of the hood release knob. You will see an 8mm stud there. Attach the large terminal end there with a washer and nut over it tightened securely.
**Special note for Comanche owners: Make your jumper wire 12" long and attach it on the driver’s side kick panel close to the fusebox on the 8mm stud.**
　
Revised 11-29-2011

cruiser54 said:

This applies up to 1990, but it COULD be the same for your Jeep. You'll have to look up under the dash.

Improving the Instrument Panel Ground
The ground point for the complete instrument cluster on your XJ or MJ is located up under the driver’s side dash. If you lay on your back and look up under there with a flashlight, without wearing a hat, you will see a black wire attached to a shiny piece of metal almost directly above the hood release knob. The screw will have either a ¼" or 5/16" head on it.
This ground point is responsible for handling the ground circuit for the following items: Dome lamps, Seatbelt and key warning, trans comfort switch, wiper switch, headlamp switch and delay module, fog lamp switch, cargo lamp switch, all instrument panel grounds and illumination, power windows and door locks, cruise control dump valve, and a few more things.
The problem is that where the ground point is located does not have a good contact with the chassis where the ground should be. The solution is simple.
Make up a jumper wire with #10 gauge wire about 10" long. On one end, crimp on a ¼" round wire terminal. On the other end, crimp on a 3/8" round wire terminal.
Remove the screw from the existing ground wire and attach the small terminal of your jumper so that the original wire and your new jumper share the same attaching point, one over the other.
Look above the driver’s side plastic kick panel just forward of the top of the hood release knob. You will see an 8mm stud there. Attach the large terminal end there with a washer and nut over it tightened securely.
**Special note for Comanche owners: Make your jumper wire 12" long and attach it on the driver’s side kick panel close to the fusebox on the 8mm stud.**
　
Revised 11-29-2011

Click to expand...

Thanks for the tip. Will most certainly try this today!

edit

Let me know if it's the same up undeer the dash in regard to the instrument panel grounds, wouldya?

cruiser54 said:

Let me know if it's the same up undeer the dash in regard to the instrument panel grounds, wouldya?

Click to expand...

Yeah I will let you know. It may be different on renix set ups.

Double check all the contacts on the instrument cluster. Get a DMM and measure resistance between the end point and the surface where the plug makes contact with each trace on the cluster. I had to troubleshoot a faulty oil pressure gauge on an '89 and after checking everything, even a different oil pressure gauge, it turned out to be a bad contact on the cluster.

Adrian96XJ said:

Double check all the contacts on the instrument cluster. Get a DMM and measure resistance between the end point and the surface where the plug makes contact with each trace on the cluster. I had to troubleshoot a faulty oil pressure gauge on an '89 and after checking everything, even a different oil pressure gauge, it turned out to be a bad contact on the cluster.

Click to expand...

I pulled the cluster and did in fact clean all the contacts on the back. Even pulling each screw. Same results. Just a wonky water temp gauge. I'll have to wait until Tuesday to use a multimeter.

**Because the idiot lights don't work either

hupo224 said:

I pulled the cluster and did in fact clean all the contacts on the back. Even pulling each screw. Same results. Just a wonky water temp gauge. I'll have to wait until Tuesday to use a multimeter.

Click to expand...

A simple clean didn't work for me. The trace was show just where it bends and the whole part which makes contact with the plug was dead. Absolutely no sign of a crack or break, just didn't carry any current.

Adrian96XJ said:

A simple clean didn't work for me. The trace was show just where it bends and the whole part which makes contact with the plug was dead. Absolutely no sign of a crack or break, just didn't carry any current.

Click to expand...

I'm grabbing a cluster from the junkyard tomorrow. Fuel sender wire did show resistance at dash harness.

Might want to grab one sans idiot light

H8PVMT said:

Might want to grab one sans idiot light

Click to expand...

What does that mean?

Tried two gauge clusters at the JY and none worked. blinker lights and headlights worked. So I have to try and trace the wires and check the grounds. What should my multi meter be on when I check resistance at the fuel sender harness and etc?

Get New cluster with gauges, not lights

Don't know for sure if this applies to your 91 or not.....

Did you ever check out the instrument panel ground?


From the factory wiring manual with a Ground Distribution page in it regarding lighting:

There are 2 points on the left inner fender.

There is the engine dipstick tube stud. SUPER IMPORTANT!!

There is the ground above the lower diagonal dash brace to the left of the steering column on the shiny part of the dash.

There is one in behind the trim panel where the spare tire mounts.

The one on the instrument panel grounds a ton of things. Probably too many things as a matter of fact, given it's poor mounting point on the panel with a self tapping screw. I remove the screw that it's held on with, add a wire, using 10 gauge, and terminate it to the stud near the fusebox.

There are also grounds from the engine to chassis, notably the poor one from the back of the head to the firewall but that wouldn't affect your dash lights. Not that the engine to chassis grounding shouldn't be addressed.

H8PVMT said:

Get New cluster with gauges, not lights

Click to expand...

Oh well I went with both because it's attached and easier to get in. But the gauges and lights don't work. Just the blinker, headlights and maybe the check engine light.

By this I mean the small circular lights on the dashboards. Worked on all 3 dashboards. So it's not a bad dash.

cruiser54 said:

Don't know for sure if this applies to your 91 or not.....

Did you ever check out the instrument panel ground?


From the factory wiring manual with a Ground Distribution page in it regarding lighting:

There are 2 points on the left inner fender.

There is the engine dipstick tube stud. SUPER IMPORTANT!!

There is the ground above the lower diagonal dash brace to the left of the steering column on the shiny part of the dash.

There is one in behind the trim panel where the spare tire mounts.

The one on the instrument panel grounds a ton of things. Probably too many things as a matter of fact, given it's poor mounting point on the panel with a self tapping screw. I remove the screw that it's held on with, add a wire, using 10 gauge, and terminate it to the stud near the fusebox.

There are also grounds from the engine to chassis, notably the poor one from the back of the head to the firewall but that wouldn't affect your dash lights. Not that the engine to chassis grounding shouldn't be addressed.

Click to expand...

I'll check all this tomorrow in the day light. Thanks for the info! Tough to find a proper wiring diagram.

btw it is a 1994

there was no number 17 fuse......

this last owner must have been stupid.