craiso

Good afternoon all.
The Part Time light on my Jeep has never worked when I use 4WD. I know the light does work because there have been a few times where my transfer case has gotten very hot while in 4WD, and I saw the light on. Please take a look at the photo. What switch is next to the ID plate? Does this switch control the light? This is on the 1991XJ.

cruiser54

Unplug that connector. Run a jumper wire between the pins on the harness. The light should illuminate.

investinwaffles

You can jump the connector to test the actual light bulb in the cluster.

If it lights up, more than likely you need to adjust the transfer case linkage to get it back into alignment. Mine is pretty finicky and it took some adjustment to get it to turn on reliably when I am in 4wd. I can put pressure on the shift selector and the light will go on/off because of how narrow the range of motion is.
Possible that the sending unit is bad too, but I doubt it

craiso

The top part of the switch has some play to it. The rest of it is fixed solid to the transfer case. I tried to jumper it with some lock wire to get the light, but apparently I did not get the wire into the plug. The part that comes up as a replacement for the '4WD switch' looks nothing like what I have; see the switch below.