2001 Chevy Blazer 4X4 shifting problem

VACERO

MEMBER
2001 CHEVROLET BLAZER
6 CYL
4WD
AUTOMATIC
147,000 MILES

We have had trouble with the electronic control on our chevy Blazer with auto 4x4 selection option for several years now to the point we had the garage disconnect it until we could have it fixed. It would shift on it's own when in 2 hi mode to 4 low( not in auto mode) driving down the road so you can see the problem that could cause. It also would slip out of 4x4 mode on its own, again, not from auto mode. It would lock in any mode and would not shift no matter what we did, to the point the garage disconnected it until we can have it fixed. The dealership wanted us to buy a new electronic control card at over a $1000. Bucks before they even looked at it and another garage wants $1500 just to check it out and see what they find, so you can see why it's still not fixed. Any help would be greatly appreciated.

2 Replies

TUNEUP1200

MEMBER
18 POSTS

You will need: small screwdriver, q-tips, and rubbing alcohol.
Pop out the 4WD button assembly from the dash. Unplug the the two wire connectors. Hold the button assembly in your hand face down. Make sure you are in a place that, if you were to drop something small you can find it easily, but lets just hope you're careful. With a small screwdriver, pry the back of the assembly from the front. Remember to keep the face down in your hands at all times. You see those blue boots with metal contacts on them? These are the things that will fall out easily. Take your time, remember where these boots are located they will pop out easily. In fact, have someone with a camera ready to take a quick picture of it before going further. Now with a q-tip dipped in alcohol gently clean the metal contacts in the blue boots. Then, with the q-tip and alcohol, clean the whole face of the board that the blue boots come in contact with, paying close attention to the white circle patterns on the board. They may not look dirty but it doesnt take much to make this assembly act nutty. When done cleaning and parts a fully dry, re-assemble and give it a try.