Gauges dead, had been intermittent for several years

Tim5276

New Member
Joined
Mar 9, 2020
Messages
9
Location
United States
Gauges have been intermittent for at least the past couple of years. Often would not be on after rain, but once the engine was started, the gauges would eventually come off. This was so intermittent that it was hard to diagnose the problem. This past fall gauges went out completely. I’ve done some minor problem-solving for the popular fixes and none have worked. Figure best place to start is making sure all grounds are good. Could anyone give me advice on ground wires to check first?
 
First things first, the factory service manual can be found in the resources section on this forum. Wiring diagrams are in section 8W, but can be somewhat complicated to read because they're laid out by functional area, and you have to jump across many pages to find your way. But because I'm recently laid off and enjoy the wiring, I'll take you through what I did you answer your question. Teach a man to fish, as it were.

I happened to already know that the cluster is connected through 2 connectors, C1 & C2. The pinouts are found on pages 8W-80-22, 23. Pin 9 on C1 and pin 6 on C2 are the ground wires. They're both BK/LG (black with a light green trace), 18ga wires which are part of circuit Z2.

1673026833602.png


Section 8W-15 is the ground distribution chapter, and page 8W-15-1 has the index. Instrument cluster is on pages 8W-15-5 (assuming you have a LHD), and it shows that both wires are grounded at G201. You can see these are the same wires because they're the same color, gauge, part of Z2, and also correspond to the same 6 & 9 pins. If I knew/remembered this section existed I would've gone directly here. I find that it's usually easiest to start at the connector, because I can start to build a full circuit schematic in my head if I start there.



1673027394269.png


Section 8W-90 has the connector & ground locations, and you can see that G201 is found "Left rear of instrument panel" in figure 17. From the looks of it, it appears to be on the back side of the dash, behind/below the driver's side speaker. "ish." So to answer your question, that's where the instrument panel grounds are found.


1673027565253.png


1673026700761.png



* I did these lookups on a different computer. I may come back and add screen caps because I'm bored.
 
Last edited:
Intermittent instrument cluster problems were common in early model year TJs, my '97 had the same problem. The common fix, which completely fixed mine, is to remove the cluster and then VERY slightly bend each of the gold-plated male pins inside the connectors to put the smallest possible barely perceptible bend into them. That causes the male pins to make a better electrical connector which usually fixes the problem. As said, this is very common and this fix usually works for everyone with an early model TJ.
 
First things first, the factory service manual can be found in the resources section on this forum. Wiring diagrams are in section 8W, but can be somewhat complicated to read because they're laid out by functional area, and you have to jump across many pages to find your way. But because I'm recently laid off and enjoy the wiring, I'll take you through what I did you answer your question. Teach a man to fish, as it were.

I happened to already know that the cluster is connected through 2 connectors, C1 & C2. The pinouts are found on pages 8W-80-22, 23. Pin 9 on C1 and pin 6 on C2 are the ground wires. They're both BK/LG (black with a light green trace), 18ga wires which are part of circuit Z2.

Section 8W-15 is the ground distribution chapter, and page 8W-15-1 has the index. Instrument cluster is on pages 8W-15-5 (assuming you have a LHD), and it shows that both wires are grounded at G201. You can see these are the same wires because they're the same color, gauge, part of Z2, and also correspond to the same 6 & 9 pins. If I knew/remembered this section existed I would've gone directly here. I find that it's usually easiest to start at the connector, because I can start to build a full circuit schematic in my head if I start there.

Section 8W-90 has the connector & ground locations, and you can see that G201 is found "Left rear of instrument panel" in figure 17. From the looks of it, it appears to be on the back side of the dash, behind/below the driver's side speaker. "ish." So to answer your question, that's where the instrument panel grounds are found.


* I did these lookups on a different computer. I may come back and add screen caps because I'm bored.

Awesome. I’ve had the dash apart, and cleaned the connections and put it back together with Dielectric grease in the past and know that that hasn’t helped, so I want to double check the grounds and just make sure I haven’t missed anything with that first. So hopefully I’ll get to this tonight or the weekend and your information will definitely help.
 
Awesome. I’ve had the dash apart, and cleaned the connections and put it back together with Dielectric grease in the past and know that that hasn’t helped, so I want to double check the grounds and just make sure I haven’t missed anything with that first. So hopefully I’ll get to this tonight or the weekend and your information will definitely help.

I added pics.
 
Intermittent instrument cluster problems were common in early model year TJs, my '97 had the same problem. The common fix, which completely fixed mine, is to remove the cluster and then VERY slightly bend each of the gold-plated male pins inside the connectors to put the smallest possible barely perceptible bend into them. That causes the male pins to make a better electrical connector which usually fixes the problem. As said, this is very common and this fix usually works for everyone with an early model TJ.

I’ve cleaned the pins and applied dielectric grease, but never tried this hack/trick, I’ll let you know if it works
 
  • Like
Reactions: Jerry Bransford
So I checked ground over the weekend that looks good. Adjusted pins to make sure they had good connections.
I also get warning lights with left C1 female connector in contact with male C1 pins on back of gauge cluster and C2 not connected at all. If I do the opposite and only connect C2 female and male connections I get nothing. As if there is no power going to C2 pin connector.
Where does power to C2 pin connector for fuel, Odom, temp, mph, volt, rpm come from? Is it directly from fuse panel? Or is there another source?
 
So I checked ground over the weekend that looks good. Adjusted pins to make sure they had good connections.
I also get warning lights with left C1 female connector in contact with male C1 pins on back of gauge cluster and C2 not connected at all. If I do the opposite and only connect C2 female and male connections I get nothing. As if there is no power going to C2 pin connector.
Where does power to C2 pin connector for fuel, Odom, temp, mph, volt, rpm come from? Is it directly from fuse panel? Or is there another source?

Have you gone through the wiring diagram in the FSM like I showed you?
 
But you can just put a voltmeter on pin 9 of C2 against a known good ground to see if you get 12V.

1673026833602-png.389643
 
So did you try my suggestion yet? It was the common successful fix for early TJs instrument cluster problems.
Just following the thread myself and found that the almost imperceptible pin bending may have done the trick. I have an 01' so I'm not sure if it qualifies as an early model but I'll know for sure if it fixed the issue when I drive it around town, Thanks!
 
  • Like
Reactions: Jerry Bransford
UPDATE: I took it to a shop when things got over my head. They are reporting everything looks good until they get to the actual gauge cluster. They’re recommending I purchase a used gauge cluster and of course I’ll then lose my original mileage. I could try to get a gauge cluster with mileage that’s at least close, but is there anyway around this that I’m missing, or is this the easiest fix if it is the actual cluster?
 
Have you performed the instrument cluster actuator test where the cluster runs a self diagnosis mode? Only reason I ask is I don't see that specifically mentioned in the thread. If not see the FSM, Section 8, in the TJ Resources section for the necessary steps.
 
  • Like
Reactions: hear