'Service 4WD' Indication

[DMaxCaptain]

About 4 weeks ago with 1000 miles on new '03 GMC, I got a 'service 4WD' indication on the information center. Per the operations manual, I pulled over, shut it down and restarted. The message was gone so continued to operate. Message re-appeared latter that day and after every start of the engine. Took truck to dealer and they stated that they were having alot of trouble with the electronic shift selector buttons in the cab. However, after trouble shouting the problem, they informed me that the problem resided in the transfer case accuator motor. Unfortunately, the motor is on national back order and to date the problem has not been fixed. Truck is drivable in 2WD (4WD not to important here in Tucson, use it only to pull the boat out of the water).
Dealer says that this is a new part for '03 and that is the eason for the delay in receiving the part...

[waterlogged]

I've seen this problem quite abit. These actuater motors are suspect to moisture just like the transmission p/n switches people have been having problems with. Just a tip, ask your dealer to do a locate on the part to see if another dealer has one on his shelf somewhere else, they can do this nationaly and gm will pay the frieght. At a risk of sounding too old school but I'd rather have a manual shifter then this motor to do my shifting.

[Runaway]

Just happened to me this afternoon. Shut truck off, but the message came back when I restarted. Went on to do my errands, two hours latter I restarted the truck and all was well. Will see what happens tomorrow. This isn't good, leaving for Wyoming in about a week where I might need the 4x4.

[DMaxCaptain]

Took the dealer 2 weeks to get the 'accuator motor' from GMC. They replaced the part last week. The next day, got yhe same 'service 4wd' message without the strange indications on the 4wd electronic shift buttons that I had before. Took the truck back to the dealer and was told that the same trouble code was present (the accuator motor for the transfer case). The data has been sent to GM troubleshooting techs with hopefully an answer this week...

[AbqGeorge]

Quite a few of us have had the 2WD/FWD dash selector switch replaced. On my '01 it failed at less than 2,000 mi. Hope they fixed it for '03?

You mentioned you had "strange indicator lights"?? When mine went out the LED in the selector switch would be very, very dim.

I recall someone on here saying they repaired that dash switch. Had a bad solder connection on it.

Thanks for the post. Let us know if it's the selector motor.

[Silver Bullet]

I have seen this twice...on my old Z-71 and a friends 2500. In both cases the control module (I think that is what it is called) mounted down on the PS fron axle had a loose connection...the problem was resolved by unplugging and replugging wire into module.

[Tommy turbo]

There is a ground connection behind headlight switch that if loose will set that code for accuater motor. It is very hard to reach or even see but this is likely the problem. Have fixed a couple of trucks with same symtoms.

[jmckelvy]

There is also a ground connection on the firewall under the hood beside the brake booster that can cause this problem or worse if it is loose. This happened to me.

[DMaxCaptain]

Just an update. Took truck back to dealer yesterday and they replaced the 'decoder module' (described by tech as the module between 'accuator unit' that was replaced previously and the selector switches).
Picked truck up and had to drive to Phoenix. On way home, yes you quessed it, the 'service 4wd' indication returned. Truck is back at dealer this am for further troubleshooting.
Thanks to one and all for the suggestions for grounding. Took all posts and gave them to the tech (hopefully he will read them).
Happy Holidays to all...

[DMaxCaptain]

Another update...
5th return trip to dealer to day, still getting sporatic 'service 4wd' messages on the DIC. So far, tey have replaced the TCCM twice, the decoder module, inspected and cleaned 2 ground connections and traced all wiring. Today, the service manager informed me that GM tech services has informed them not replace any more parts, that the problem is software related and that an update is due in a month or two. $wd works fine, just an anoying message that appears...

[ski]

I have on 03 also and had the same indications twice. There is a TSB regarding this for the 03's. It has been a month but IIRC, it was a problem that involved software in one of the control modules. Have your dealer do a TSB search on it.