I have an 03 4dr blazer. Most of the time all the 4wd lights are off. From time to time the 2wd light will be on. In any gear other than neutral nothing happens when I push any of the 4x4 buttons. In neutral no matter which button I push (2wd 4hi or 4lo) the 4lo light blinks and they all turn off. The truck remains in 2wd. I was wondering where should i start with the issue. The truck sat for a littoe over a year and I think it worked before I had to park it.

 

Is it the 3 button or 4 button 4wd????
If it is the three button, do you hear a noise under the cab when you shift into 4wd?. If not, could be encoder motor. Light issue could be the TCCM.

If it is the 4 button, not familiar with that one..

 

It's the 3 button and the only noise i hear is a clicking sound coming from the area behind the glove box.

 

Sounds like your encoder motor is not shifting the transfer case. Could also be the buttons on the dash are bad and not sending the signal for the encoder motor to switch.
The Tccm sends the voltage to the encoder motor and keeps track of the good shift vs bad shift so it could be bad too.

Sounds like you have some electrical troubleshooting to do..

Goodluck

Bill

 

What would be the best way to test those three?

 

Ok... I pulled the tccm and ot has rust on the casing and there were spider webs around it (I had the truck parked for a year or so) the pins look very clean as does the harness. Is there a way to test it now that I removed it?

 

The TCCM is in the kick panel passenger side next to the front door, Remove the kick panel and disconnect the cable let it set for about five minutes then reconnect it. Maybe the TCCM needs to be reset or it is bad. One from the junkyard is not that expensive.

With the symptoms you provide, the issue with the switch, and encoder motor, sounds to me like the TCCM is bad.
I found them on Ebay for around $65 used and $275 new..

Maybe some one else on here has a different approach to your situation..

Bill

 

I know there are ways of troubleshooting it, however I am not the one to talk with. I am sure some one else here can help with that.

If it were me, based on your description of the TCCM and surrounding environment, I would replace it.

Bill

 

I put the tccm back in last night and waited until this morning to hook the battery back up... It's still doing the same thing... Nothing happens when I push 4hi no matter what gear I'm in... When I'm in neutral and press 4hi the tccm clicks twice while the 4lo button blinks then either the 2wd light comes on or they all stay off.

 

Somewhere on the web is a guide to read the lights to diagnose the TCCM. Still could be the encoder motor. You could remove it and manually shift the transfer case to make sure it is okay. Could be a transfer case issue and the Encoder motor can't shift.
Also, still could be the TCCM. You should be able to shift in 4hi while moving in 2hi. To get to 4lo you have to stop and put the transmission in neutral then push the 4lo button. If this doesn't work back to pulling the encoder motor and make sure the Transfer Case is not broke..

Bill