What does it mean when the 4x4 light on the dash turns on for about 2 seconds after starting? The 97 F150 is stuck in 4x4 low and the electronic shift does not change anything. The front axle will disengage with the help of a hand vac pump. I moved the shift rod on the rear of the transfer case after removing the motor. The motor moves when I use alligator clips to power it from a battery on the bench. The ABCD contacts look OK with a meter.

 

Most all dash lights, and or gauges will "self test" when starting, to prove themselves out. Your problem could be a faulty switch, relay, or 4x4 module(I think it is inside the GEM in 97). Codes can be pulled with a scan tool. Some trucks had a problem with a windshield leak causing the fuse box/GEM to get water intrusion. Usually, though, has several other electrical concerns also.

 

This last weekend I removed the 4x4 cable from the GEM controller and tested each of the incoming signal connections with a meter. I was able to activate the clutch, vac solenoids, dash panel lights, and control the motor by grounding each of the leads. The dash switch changed resistance when switched to the three settings. The speed sensor showed 300 ohms. The transmission neutral switch showed a ground when in neutral. The brake switch showed 12 volts when depressed. I am going to look for other failures that don't relate to the 4x4 controls. The GEM board has one large custom IC and not much else. I collected a few spare connectors from the junk yard and would like to build a simple exerciser for the test bench that would let me look at signals on the test bench. The board should have been conformal coated at least by Ford when built. It appears that my board was used in 97 and 98.

 

Replaced the GEM module and it works correctly. Found used one at junk yard from a 98 F150 for 20.00. Now I can start fixing the other items that need attention on the truck. The factory manuals and Mitchell's sure helped. The 97 and 98 GEM's sure have a lot of different part numbers. Plan to use some conformal coat before I finish putting everything back together.