4wd drive stopped working and lights on selector will not come on

If after driving a little bit the 4wd light starts blinking then I believe one (or both) of your HALL sensors are bad or have picked up some metal filings.

I believe the light is blinking because your GEM computer doesn't think both driveshafts are going the same speed.

I think one of your HALL sensors is fooling the GEM into thinking one of the driveshafts is stopped all the time

When you are stopped the computer thinks everything is OK (because the other driveshaft is stopped also)

When you are moving the GEM tries to get both driveshaft spinning the same speed but the sensor isn't responding

It takes 5 minutes to change the rear sensor (you have to cut the old one off and splice in the new one. Sealing the splice with liquid electrical tape)

The front sensor is hardr becasue you have to remove the shift motor on the transfer case

also for the 4wd system there is a TOD(torque on demand relay) that might be bad

Change fuse and test.

The fact that it flashes 5 times means that it is trying to tell you what is wrong, you may have a faulty selector unit

Is your battery light on the dash on? When my alternator died, my hubs were auto locking due to low voltage in the 4wd selector even though 2wd was selected. The problem corrected itself when I installed a new alternator.

Well it could be the selector switch, but I doubt it.
Generally, the service light means something is not working that the computer controls. Solenoids and valves are a couple of possibilities.
The transfer case is shifted by solenoids commanded by the body computer based on the switch position on the dash.
You should be able to have a shop scan the body computer for trouble codes and proceed from there.
A basic code reader may not access the body computer.

At www.reliable-store.com get complete guide on whether to repair or not, service it, and how to repair etc, along with wiring diagrams, electrical diagrams, torque specs, error codes, everything.

I have run into to this problem many times on these trucks, i have seen your problem and also where the 4wd high light wont work but 4wd low and 2wd work fine and the 4 wheel drive works fine. on your truck i will bet its the transfer case selector motor.
the motor is what turns the lights on when in the selected mode which goes through the 4wheel module under the dash, this sounds like a bad selector motor and that where i would start. this motor is located on the transfer case, it bolts to the rear of it.here is a picture of it to help you locate it. good day.

I would find an independant shop that has a Tech 2 or equal scan machine....these can communicate with your TCM (Transfercase Control Module) and narrow down what the problem is.

same problem , anything???? debiangnu at sbcglobal dot net

I questioned the dealer about my 2005 because mine was disengaging what I thought to be rough compared to what I was used to. They told me that I should shift the vehicle into Neutral before shifting the selector. I have also found that shifting between Reverse and Drive a couple of times while stopped has helped as well. By doing these couple of things, I have had no trouble since. I hope this helps as it might at least be something to try.