Quote Originally Posted by FMS88 View Post
It could be several things, but first check the wiring harness. Start with fuse #7. Make sure it fits tightly and isn’t corroded. Then inspect the harness starting with the two wires to the pulse generator, which is the flat, circular protrusion from the rear of the transfer case. It’s opposite the front drive shaft. Locate the connector for the pulse generator which is above the round mount on the driver’s side of the transfer case. Separate this connector and clean the contacts. Cleaning these contacts fixed the same problem on my truck. There’s also a connector in the engine bay that should be checked. It’s to the right of the wiper motor.

if the above doesn’t correct the issue, check the contacts and connector to the 4wd hub indicator control unit. The unit is near the floor behind the plastic guard to the left of the driver’s left foot. It could also be the bulb or harness connection to the gauge cluster. If you pull out the cluster, don’t bend or crimp the speedo cable. Doing so can damage it.

Good luck.
Correction to my previous post, above:

The harness description is for my 88. I just checked and the 92 differs from the 88. The 4wd hub indicator control unit is on the passenger side behind the plastic cover to the right of the passenger’s feet. Also, the connector near the wiper motor on the 88 is in the cabin on 90+ models. In the service manual the connector (#D-24) appears to be below the dash above the tunnel. I don’t have a vehicle to check. Perhaps an owner of a 90+ 4x4 can confirm this.