service 4wd

I've been getting a service 4wd light come on recently. It comes on mostly in stop and go traffic, when my outside thermometer reads between 69 and 71 degrees. It will also come on when on the highway at speeds in the upper 70's to low 80's.

It's a 2001 Sierra with 5.3L, auto.

Any help out there?

i recently had my Service 4WD light come on as well but my circumstances were different. it would do it only when i started it cold and it would turn off very quickly. i replaced my electronic 4WD selector switch (4WD push button device next to steering column) because it would make several "ticking" noises when starting the truck and someone in here told me it was the culprit. the OEM part cost me $60 from dealer and i haven't had any more problems with it.

I really don't know enough about cars to suggest your problem is the same as mine, but no one has responded to your post so i thought i'd just throw in my 2 cents and that could at least be a starting point.

tbacon1
1999 Chevrolet Silverado, 5.3L engine, Auto Trans., Electronic 4WD

Its the switch...mine did it too.

Mine too.

'01 Silverado 5.3

Hey all, I made the mistake of buying a truck over eBay because I thought I got a good deal, but its not quite what I thought it was... My biggest problem is that the service 4WD light comes on periodically and I cannot figure out what the problem is. I took it to a GM certified tech and they said it was the switch but wanted $130 to replace it, so I just bought a new switch and put it in myself... Same problem. Does anyone have any ideas on what it could be? My front right tire is significantly more warn (approx 1/4") more than the others and I was wondering if there was any kind of sensor on the truck that would sence this and keep it from going into 4WD so I didn't shread the transfer case? Does anyone know anything about this? I am running Maxxis Buckshot Mudders @ 285/75/R16. Thanks!