Fixing your part-time 4x4 dash light after a front axle swap.

[Airborne Janitor]

I combed through the archives and was able to figure out how to fix this issue. I have an 89 MJ that I swapped a 97 XJ NP231, AW4, and Dana 30 into. Since I got rid of the vacuum disconnect components which is part of the operation of the Part Time light on the dash, I no longer had my light engage when putting the case into 4wd. So I made a little write-up. Not sure if it works for those with a full-time case so YMMV.

 

1) Test your part-time light. There's a wire in the main harness on the passenger side fender near the firewall that's a female bullet style terminal. Mine had 2 black/red wires coming out of it. (Sorry forget to take a photo of the bare plug). Run a jumper from this terminal to a ground, then put your keys in the ignition and turn it on, your Part Time light should light up. 

 

2) The bullet terminal is a bit larger than anything I had in my toolbox that would fit. But turns out if you have a spare trailer harness lying around the terminal on those are a perfect fit. So I cut one of the wires off the trailer wiring.

 

 

Fits like a glove.

 

 

3) Build your harness. You will need the plug end going to the 4x4 switch on the t-case. I used 5ft and 2ft of wiring and put a ring terminal on the end of the 2fter. 

 

 

All tidied up.

 

 

 

4) I ran my harness down the passenger side firewall, following the cables leading to the top of the AW4. Grounded the switch to the exposed bolt threads on the old 4x4 shifter linkage. Note that I got rid of the stock linkage and installed the Azzy Design one.

 

 

 

 

5) If you did it right, throw your case in 4HI and 4LO and see if your dash lights up.

 

 

So easy a caveman can do it.