service 4WD light

[PDW HOTRODS]

I have a 2001 GMC 4WD 1/2 ton, and the service 4WD light comes on. Does anyone know what this means? Also I think the 4WD switch is going out. When I go from 2 to 4, sometimes it won't switch. I think I herd somewhere that there was a recall on the 4WD switch, and it might need to be changed. Thanks.

[Palf70Step]

A guy I worked with had an issue that sounds just like yours on his 2003 it was a bad switch. I don't remember if it was the dash switch or the item on the transfer case. His was covered under some recall or warranty fix. (this was back in 05)

[67ChevyRedneck]

I could not find any info on a recall for the 4x4 switch. Maybe GM is replacing them on good faith...because MANY have failed.

My truck is doing the same crap and I'm pretty sure it's the switch, just too cheap (and unemployed ) to swap it. They're about $60 from either ebay or gmpartsdirect.com. That's where I've found them the cheapest. I'll swap mine when I get some extra cash. They're real easy to change. The dash face pops right off (you need to drop the shifter down to 1st get it around the shifter). Push in the tabs and it pulls out, push in the tab on the pigtail and the wire pigtail should come right out. Supposedly you can repair them by taking it apart and resoldering the connections, but I took mine out and couldn't get the stupid switch apart, so I put it back in.

[fireunit29]

My 99 was doing the same thing and I replaced the dash switch and have no trouble switch to 4 wheel drive or seen the message again.

[cheyenne402]

My 2000 HD did the same thing. Replaced the switch and all is fine now.

[Waylon]

My wife's '04 Tahoe does this.

I was researching earlier and came across a TSB.
02-04-21-006E
I also read that removing and reinstalling the all wheel drive fuse while it's running, sometimes cures the problem.

[Alan Potter]

Here's what I did........Since my 2003 Tahoe has over 100,000 miles I went ahead and changed the oil in the trans axle, figuring it probably need that anyhow, but the "service 4wd" stayed on until I disconnected the battery cable to reset it. So I'm not sure which of those two procedures fixed the problem, but the light hasn't come back on!

[Boog]

All of these messages are explained in the owners handbook if you have it. Like the "change oil" message it's a mileage thing and the "service 4wd" message may also be a reminder due to the mileage. The handbook even tells you how to turn off these messages like after the oil change, turn the key to on and fully depress the gas pedal 3 times in 5 seconds then turn the key off. Restart and the message will be gone.

[Gray Ghost]

Or if you have steering wheel control buttons, pull up the oil % and then press/hold the enter button for a few seconds until they reset.

On mine, I reset both trip meters and the oil % message at the same time.

[Cdshinne]

Had the same problems on my 2000, put a new switch in, the light went out and i have no problems what so ever switching 2 to 4 anymore.

[DirtyLarry]

Originally Posted by Boog

Like the "change oil" message it's a mileage thing and the "service 4wd" message may also be a reminder due to the mileage.

Ah, no…the “Service 4wd” only comes on when there is a problem with the 4wd system. The light is not any kind of service reminder.

The reality is electric shift 4x4 system in these trucks is junk. Period. Same with Dodges as it is all the same suppliers of encoder motors and Delphi TCCM’s and control heads. There are 4 electric pieces of junk and 9 lbs of harness to do what a simple lever used to do very reliably, I might add.

The most likely issue is the control head in the dash (the switch with the buttons). But the transfercase encoder motors on the side of the transfercase often fail as well especially in the roadsalt throwing states. If that wasn’t bad enough, the transfer case control modules (TCCM) aren’t the most reliable piece either (the TCCM is also the most expensive). Then there is the electric front axle disconnect that is a terd in itself.

There are just too many things to go wrong with these electric shift 4x4 trucks. Makes you wish you would have bought one with a lever. I went out of my way to find manual shifters in both of my HD’s. Unfortunately, the Tahoe has Autocrap electric shift as standard equipment. And yep, it has already had the control head changed once at 23,000 miles. Junk, I tell ya…junk.

Anybody see the new 2010 Toyota 4Runner? Even Toyota went back to a manual shift transfercase.

[Gray Ghost]

So is the manual shifter cable operated, linkage operated or a switch as well?

[DirtyLarry]

Originally Posted by Gray Ghost

So is the manual shifter cable operated, linkage operated or a switch as well?

The manual shifter has a mechanical linkage that runs directly from the shifter to a selector arm on the transfer case....just like the good ole days. There is still one electrical gremlin on the manual shifters though and that would be the electric front axle disconnect, basically an electric version of the old manual locking hubs. There is a mechanical cable operated disconnect available for ’88-’98 trucks through a company called Posi-Loc while there are no alternatives for ’99 and later models unfortunately.

You can still find trucks with manual shifters if you look hard enough in WT and LS trucks (Electric is standard on the cream of the crap trucks). Here is one in a 2010 Silverado on Ebay with one.

[Gray Ghost]

I have the pushbutton version....so far no problems...hope that holds out.

Gotta agree about the 900's....ugly trucks indeed.