Service 4WD light

scrver · October 13, 2005

Yesterday morning as I was pulling out of my garage I got a "service 4wd" light on my odometer panel along with no lights on the 2,4 high, 4 low indicators next to the buttons. I have a 2004 Sierra 2500HD with 7900 miles. I called my dealership and they came right out and picked it up from my job. I picked it up later in the day and they said no codes were found. They reflashed the computer and made software upgrades. After quetioning him further they said that they have had several brought in for the same reason, same cure, and no returns. I read this forum quite often and have not seen this before. Anyone else have this problem? What was your cure?

asilverblazer · October 13, 2005

A lot of times it is the switch, but if what they did fixes it, well.....

Yukon04 · October 13, 2005

My 00' Sierra had the same symptoms. It was a bad switch. Found a pick-your-own junkyard and replaced the switch for $10. Everytime the dealership looked at it, ofcourse it behaved normally. Fixed my issue, cost me $10.

bdeboer · October 13, 2005

I had to replace the 4x4 switch in the dash on my 1999 1/2 ton for this. From what I understand this was a common problem on the first new body style trucks. Some guys actually take them apart and resolder the connections. I am not sure if this still a problem or not.

2wheelsRbetter · October 13, 2005

I had something similar happen over Labor Day weekend. We were leaving camp after the Truck sat for about 3 days and Service 4WD came up on the DIC when I started it up to leave.

About the only thing unusual that happened that weekend was that the wife set off the panic button by accident in the middle of the night. Fellow campers were not happy due to the 4:00 am wakeup call from the GMC.

I'm thinking that she may have started pushing buttons on the dash trying to get the thing to shut up.

I tried everything to get it to work. It almost seemed like it was going crazy switching to 4WH High to Low to scrolling through all the lights on the panel. I still wish I could have got the old trustworthing manual linkage with the center console, but no dice.

All is good for now once it found itself. I thought for sure the truck was going to leave us stranded on our 3 hour return trip. No problems so far, but I also haven't had to put it into 4wd that often since it occured. I'll look into the switch issue if it occurs again.

05HD · October 14, 2005

There are TSBs out for both issues, the switch and the "phantom" service 4x4 light. Once the problem is determined by the correct diagnostic steps, the new switch or the TCCM reflash will definitely take care of the issue. <Hugs floor shifter>

JRKRACE · October 14, 2005

Switch went on my 2002 the same way...Try pushing the swich in different areas to make it flex. I did this and the lights on the switch would flicker on and off.

scrver · October 14, 2005

Thanks for the responses. I will post again if it comes back on and I will definitely remember the switch problem. One of the things that disturbed me was when I asked the question of "what happens if I am in the woods or field and this happens? Is there any thing that I can do to make the 4wd work? The response was "no". Hope my luck is good!

CdnChevy · October 16, 2005

Our 04 did the same thing, just came on. Took it in and they said their were bullitans out on it and they sent down a new software version down. Been fine since.