2000 Blazer service 4x4 system warning light

[raiderman]

New guy here, I hope someone can help. I have a 2000 blazer LT 91k I was testing my 4x4 system for the impending winter snow and when I pushed the button the "service 4x4 system" warning light came on, I also heard a clicking sound from the passenger side under the dash,also the lights on the 4x4 buttons would not stop flashing for a very long time, and it was very difficult to put it back into 2WD. The warning light will go off if I put the truck back into 2WD and restart it. I have also noticed a wining sound when driving in 2WD, it'll get higher pitched when I speed up. Can anyone help?

[BlazerLT]

Yes, you need to replace the electronic encoder motor.

Do NOT drive it when it is whining like that.

That is a transfer case that is not out of gear properly.

[Alexxn 00 Si]

Same EXACT thing happened to my 2000 Blazer.....I would suggest checking the vacuum switch on the transfer case to see if the check ball is stuck before you drop serious cash for the encoder motor....that's what was wrong with mine - $15 part. HTH

[raiderman]

Well, I'd like to thank you guys for the tips..but here's what just happened I went under the truck to find the vac switch, I could not even get to the top of the transfer case. NO room at all. Is it located to the side or something? Well any way after looking around under the truck and I found a electrical conn. on the side of the transfer case I cleaned it and made sure it was pluged in tight. Note...I did nothing else..Then when I was checking the 4x4 buttons to see if they worked I had the following happen...1.I can only get the truck in 4w auto and 4w hi, when I try to put it into 4w low or 2w the lights flash and go back to 4w hi...2, I can hear the motor on the transfer case making a buzzing sound and 3, I hear a clicking sound coming from the passenger side under the dash, and when I started to back out of the drive it would hardly roll and was locking up and making a clunking sound, this also happened when I was pulling forward. Holy crap what the....is going on with this thing. Any futher help would be cool.

[BlazerLT]

Ok, the clicking is the 4x4 relay, that is normal.

What you are seeing is the failed encoder motor not properly switching the transfer case.

This is common with most electronic 4x4 Blazers and jimmys.

I suggest you replace it. It is fairly easy to swap in.

[swalt]

Can any of you guys confirm on the 2000 Blazer if the service 4x4 light lights up when you first start up the truck to verify the bulb is working? Mine has never lit up since I bought the truck, and I don't know if the bulb is defective.