The 4X4 could be the actuator solenoid.

To reset the computer do this.

Disconnect the Neg side of the battery. Go inside the truck and depress the brake pedal for 30 seconds. Reconnect the Neg. Start the truck without touching the throttle and run it for about 15 seconds. Turn it completely off. Restart the truck and drive as usual. It will take at least 12 starts and 48 miles to fully retune.

 

Wow...thanks for the quick response. I feel like I should be paying you guys for the advice

Is that an expensive fix / hard to DIY?

Cheers!

 

Before I drive it, will the 'service 4WD' light be off or will that disappear after the 48mile retune?

 

Well it is on 2 different systems. If it is just the accuator it just means it's stuck, broken or shorted. Computer reset won't help I don't think but at least you'll do it right. As for the 4X4 it could have something to do with the CTM so I just wonder if it might help.

Did you spray the wiring harness outside of the cab?

 

Yup, I sprayed the wiring outside of the cab. I had to bring the D into a tranny shop because I did all that I could. Checked the fuses, got a friend of mine to hook up a reader to the computer..no codes available to be cleared...

I really don't know where to go from here.

 

Have them blow out all the male and female connectors with compressed air.

This light has nothing to do with the OB-ll and the PCM so it will not store a code because they are not hooked together.