4WD issue

[vagator]

After starting the Envoy after work this afternoon the "Service 4WD" light was lit and remained on for the short commute home. The lights on the 4WD switch were not on. I turned the ignition off, restarted service light again came on. Turning the 4wd activation switch did not result in noise from any actuator.

After dinner I pulled the 4wd fuse. Waited a minute and replaced. Started the truck, no warning lights, placed it in 4 hi successfully. No apparent issues.

Should I do anything else or forget about it for now? Appreciate any and all inputs. Thank you.

[TBYODA]

First how miles, have you even replaced the transfer case fluid? A lot of repair info on GMTNATION.com

[The Roadie]

I'd forget about it. If you had a 2002 I'd say bad TCCM. As it is, you had a temporary loss of TCCM function, but a power cycle fixed it. If you offroad alone a lot as I do on dumb days, I'd get a spare.

[vagator]

Thank you. I'll start looking for a replacement TCCM.

[v7guy]

Chuck, I've had basically the same experience as you and Bill, it seems to happen occasionally. I've experienced it twice in the last 6 years.
If it happens with any regularity go ahead and replace the switch. If you haven't used the 4wd much, take a few minutes and turn the switch through all the settings several dozen times with the truck off just to keep the ole contacts clean, it's likely unrelated, but it's another source of odd problems.

As Bill stated, it essentially a non issue.

[vagator]

Strong copy on the switch. It is original to the truck, 2004 100+K, so that is on the list...along with a 8.6 rear end and locker. I think I'll get the switch a tccm first though.

[JorDaneeKey]

Ours will come on occasionally, but only under a specific circumstance: making a tight turn into a parking spot (not cranking the wheel to the stop point though) and parking. When the engine starts again, the light may be on(1 time out of 10). We're talking 1-3 times a year at most. After the second start-up, it's gone. My 02 used to do it too.

[vagator]

Interesting. I was facing south and made a fairly tight turn to parallel park on the other side of the street facing north. Shut her down for the day and noticed the light when I restarted after work. Sounds like a similar issue.