Problem with Push Button on my 1999

[leftylane6]

I just bought this truck today..I get home and decide to try the 4x4 Unit to check out how it works..It didn't seem to want to activate out of 2high..We put it into Neutural and pushed it to go into 4H..It did after a few tries and the light finally came on..We were parked..Now it seems to be stuck in 4H...We turned the truck off and on and the light came on AUTO so once again we tried to put it back into 2high with the light on...There was a loud growling noise in the Rear End and it seemed to be stuck in between gears or something when we drove...Could somebody please give me the run down on how this Works?...Is Something Wrong? Am I doing Something Wrong? Or is Something Broken?...Are you supposed to be moving when you push the buttons? At a certain speed? Or does it matter if you are parked in neutural or driving when you hit the 4x4 buttons...I thought that the push button system was Woman friendly... Oh and on the way home the Service Four Wheel Drive Warning Came On...I didn't receive an Owners Manual with this Truck and the guy that I bought it from could barely speak English...I would really appreciate any Help....Thank You...

[Z15]

You are going to have to have a GM dealer trouble shoot this. It could be one of 3 possible things. The switch is bad (if your lucky and many do go bad, more delphi junk), the control brain box under the dash or the acutator in the transfer is bad. The switch is cheap but the other 2 items are pricy (as much as $400 for the actuator) because they are electronic motors, so you don't want to change the wrong thing. There is a methodical way the dealer can solve this without buying unecessary parts.

Bet the reason it was sold it that this problem surfaced.

I had similar problem with my 2001 GMC when it was new, it turned out to be the under dash module. Later the swtich went bad.

I would be very hesitant to take it anywhere but a GM dealer. Some of the other shops may not have the knowledge to trouble shoot this problem and it could end up just prolonging it. Feel them out before you give the the truck to screw with.

[leftylane6]

Thank You So Much for the advice...I will get in touch with the GMC dealer today...I am not used to the push button stuff...I am used to the old school style...Yeah, I am wondering now if the guy I bought the truck from was just acting like he didn't understand the questions that I was asking....I appreciate You....