Got a service 4wd on my DIC, I have no lights on the electronic 4x4 switch in the dash, I have replaced with new switch but still same thing, I have done a search on this but havent came up with anything real concrete on the problem, maybe a sensor or switch on the transfer case?
I do not have a code reader, any help for me or just take it to the dealer?


Done more searches and found some info, make a long story short, I pulled the TREC fuse under hood for 30 seconds and now all works drove it, all is switching, did I prolong something or do ya thing i got lucky?
Thanks

I've got the same thing, if memory serves the early 03's had this issue commonly. Mine showed up once while under my 36k warranty. Of course now at 50k it's on almost daily. been meaning to get it fixed all summer, but just haven't found the time to drop it off. I hate to inform you, but it'll likely be back and get worse as time goes on.

What you describe sounds like an electronic "hiccup" of some sort. Maybe your encoder motor is not initializing on start-up? I had the same type of thing happen with my gauge cluster...it stopped working. I pulled the DIC/info fuse for 30 seconds, and the cluster has worked fine since.

The "service 4WD" light has been discussed here at length. If it is a part failure, the techs have said its probably an encoder motor sensor. If you are out of warranty, you can get them at www.GMdieseltech.com

http://www.gmdieseltech.com/store2/cart.php?target=product&action=view&product_id=16260&category_id=282

I think there is a TSB out on this, ive got the problem right now. Can check out my post in the drivetrain forum...