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HELP! Wiring issue after putting dash back in


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HELP!! In the process of putting my dash back in my 88’ mj. I completely gutted the interior to swap in a different dash and do the heater core. Must’ve forgot some wiring somewhere when putting the dash back in but I have no idea where. Trying to charge the battery, and when the tender is turned on this is what happens when I turn the key on and off. When the key is off, the ac compressor clicks. When the key is on the compressor stops clicking and the fuel light/cluster gauges pulse along with the seatbelt light and radio screen. And one of the circular relays under the dash starts clicking. Gauge cluster and climate control lights also won’t come on. Also does different stuff when I have the headlight switch pulled out. I’m thinking some kind of ground but like I said I’m lost. Everything seems to be plugged back in… 

Any ideas?? 😔

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6AC137E9-C826-4792-9217-2ED907B87B93.jpeg

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Hots touching me thinks. :shhh: a/c and blower share wiring on that side. So between dash switches to the heater box to the engine bay relay box to compressor. Always double check whatbyou worked on last before notice of issues. Sometimes we all have brain farts and plug it wrong, or not at all. But if your swapping wiring harness ensure the combabilty between harness years. 

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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, seat belt and key warnings, transmission power/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 share 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.
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  • 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.
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  • 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. Use a coating of OxGard at all ground contact surfaces when attaching the screw and nut.

IP ground location

**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.**

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  • 3 weeks later...

You said you swapped in a new dash... Was it an XJ dash by any chance? Something similar happened to me, swapping a complete XJ dash with harness and fusebox in my MJ. The wires on the XJ bulkhead connector don't all line up with the Comanche one. I had to find pinout diagrams from both an XJ and MJ to know where to reposition the wires in the connector.

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  • 2 weeks later...
On 2/21/2022 at 6:25 PM, Ωhm said:

I'll take a shoot in the dark here. Is it possible that the cluster connectors can go in two different ways?

 

1114519691_C203_C204InstrumentCluster_1.jpg.f34711e2f2c176db3c78f3ade21678e3.jpg

 

 

 

 

I wondered that.. I also wonder if the brown plug that goes on the back of the headlight switch could be backwards? Not sure where to find a diagram showing that. Tomorrow, I’ll look and see if my cluster is plugged in like the picture you attached 🤔

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  • 2 weeks later...

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