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Guage lights and speedometer do not work

aeheschutte

NAXJA Forum User
Location
NM
There is no lights to any of my guages at all. My dome lights and the rest of my interior lights work though. And my speedometer and miliage does not work either. the rest of my guages work though. I have already checked my fuses and they check out fine. But the only things that dont work are my speedometer, guage lights and miliage counter. Any body have any suggestions on how to fix this?
 
I'll assume you have a 91+ since your speedometer doesn't work. Pre-91s are cable-driven IIRC. I don't know which years have the digital odometer, however.

Are *any* of the gauges working at all? Like coolant, oil pressure, etc.

To start with I would pull the dash apart (should be just a few screws, if you're having to yank on it you're doing it wrong) and get the gauge cluster out. On the pre-91s getting the speedo cable off can be a pain, but on the newer ones you should have enough slack to get it out and then unplug the cables. Examine the cables to see if anything looks burned, and also check the printed circuit sheet on the back of the gauge cluster to see if any of the wires have broken or come loose.

Is this a new issue that just randomly started happening, or did you just buy the vehicle and it was already like this?
 
Your right on about the year. Its a 92. The odometer is a roll one, so its mechanical. All of the guages are working except the speedometer. I bought my XJ like this thinking its probably just a fuse. But the lights for the guages dont work either. I didnt know if the two affected eachother or not. But i will give this a shot. Do you think its just a bulb as far as the light not working?
 
Ok. I'm looking at the wiring diagram for a 92 and it looks like coolant temp, fuel level and oil pressure come directly from those sensors themselves (they don't go through the PCM). Voltmeter doesn't need to go anywhere, it just picks up whatever voltage is at the cluster. So it makes sense that those work, as the connections for them are bypassing your PCM.

Does your tach work? I would guess that it is NOT working as it comes from the PCM as well. I don't think anything is wrong with your PCM, otherwise you would be having much larger issues.

What is confusing to me is that all of these signals are coming into the instrument cluster via the same harness. So it would be weird if the harness was loose and that was causing *just* your PCM-based sensors (speedo and tach) to not work, while other sensors (fuel/oil/coolant) coming through the same harness work fine.

So it might be something wrong with the cluster itself. I really doubt that any of your bulbs are burnt out, especially when there are other issues such as your speedo not working.

Either way I think your next step is to pull out the cluster and examine things. Even if this is your DD you should be able to have it apart, out, and back together in an hour or so. Once you remove it 9 or 10 times you'll be a pro at it :)
 
sweet...well the tach works great. I will get in my chiltons and see if i can find the same diagram you are looking at. Are these clusters easy to get to once i have removed the dash and pull out the guages? I am going to try to tackle this soon. It is my DD, but like you said, I should quickly be able to find out just what is wrong from the inside. Do i need a multimeter or will i be able to visualy see something is wrong?
 
Ok, that's interesting that the tach works, I'm not sure what to make of that.

Just follow your Chilton's for getting the dash apart. Once the dash is off there should be four screws that hold the cluster in, it comes out all as one unit. I believe the lights on the side (for e-brake, seatbelt, 4x4, etc) will be attached and it will all come out together. At least that's how my 89 is, but they changed a lot starting in 91. Then there should be two harnesses, one for the warning lights on the left and the other for all of your gauges and backlighting.

I would take a look at it visually, to begin with. A multimeter would be handy to have, though. For instance, you can measure the voltage between the orange/black wire (which according to the diagram is the gauge illumination wire) and ground (I use the outside edge of the cigarette lighter) to see if there is any voltage in the harness when you flip your lights on. Then you know if it's a problem with the cluster, or in the wiring.
 
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