I took my 2002 Trailblazer to the dealership in Dec. Because the 4 wheel drive was not operating (I hadn't needed to use it in months) the wasn't any service light on the vehicle when I took it in. Magically, when I left the dealership the "service 4WD light" was on. After they charged me an $80 diagnostic fee I was told I need a new transfer case module that would cost $400. I haven't had time to take the car in over the holidays. Today when my husband was driving the car he had shut it off and just for kicks put it in 4 wheel high and it worked!! however, he was driving down the road and tried to turn the car into a gas station and it shuttered and did not want to turn. He did get it into a parking spot, put the vehicle in park and shut it off. After the vehicle was off it lunged forward about 4 feet. I called GM immediately when he came home and they said they would contact me dealership and the best they could do is pay for half of the repair!! all I can say that I thank god that there was not another car or person in front of my car when it mysteriously jumped 4 feet forward. I have noticed on the website that there are a lot of complaints about this control module-it is just an accident waiting to happen. Also, when I called the dealership to make an appointment (im afraid to drive the car) they said the soonest they could take me was on Tuesday( 4 days from now)-even after I had explained the whole situation.

- Ray, MI, USA

While driving, unexpectedly the 4-wheel drive light went off. When this occurred, it rendered the 4 wheel drive inoperative. This was caused by a failure in the tcm module. The dealership reprogrammed the tcm module, but the problem recurred. Several tsb bulletins were issued on this problem.

- Springfield, NJ, USA

Upon starting the vehicle, the service 4-wd indicator light in the console area lights up, and the setting selector light does not work. The selection switch does not light up. The vehicle is new and has only 750 miles. When the dealer was contacted, I was told the service department could not look at the problem for 10 days. Additionally, I was informed that while the vehicle is probably safe to drive until they (the dealer) could assess the problem, the four wheel drive would not be working! having just been in an accident in another vehicle that was totaled, it does not give me a sense of security driving a vehicle that is not operating properly.

- Stamford, CT, USA