4WD problems 2002 trailblazer

I have a 2002 trailblazer when i engage to 4 high it makes a loud wineing noise and somtimes going down the road it goes into 4hi by it self and last time i tried to engage it to all wheel drive it took it a while to go back to 2 wheel drive Should i look at the encoder moter or the tcm or maybe the switch what should i do?

I had the same problems w/ my 02 and then the light finally went out. As I have posted on other threads similiar to this one I found out that you can disconnect your battery for about 3-4 minutes and reconnect it and it should remedy the problem, it worked for me and haven't had a problem since.

Disclaimer: Not responsible for any damage that may occur during this process. Everything work for me.

I have a 2002 trailblazer when i engage to 4 high it makes a loud wineing noise and somtimes going down the road it goes into 4hi by it self and last time i tried to engage it to all wheel drive it took it a while to go back to 2 wheel drive Should i look at the encoder moter or the tcm or maybe the switch what should i do?

That happened one month before my tcase blown, Gm kept saying it was the encoder motor acting up. I guess they were wrong. BE very careful.