hey all...

i have a 2001 Blazer that is currently stuck in 4 LO. (and the Service 4WD light is on)

A while back it was acting up and I scraped off the green gunk on the TCCM (which helped), but now it's permanently stuck.

While investigating, i also have a wire 'cut' going into the passenger side front tire (presumably for the ABS which would explain why the ABS light has been on forever)

I used to hear the relays in the TCCM click, but now they never make a sound.

I checked voltage at the 4 pin connector on the TCCM and there seems to be Battery voltage (14+ while running) at pins 1,3,4

the switch on the dash is responding to my presses, just blinks and eventually returns to 4LO.

I think you're going to tell me to check for voltage at the encoder motor, but i'm not sure where that is. to me, it seems the problem is before that due to the lack of relays clicking..

thoughts?? any help is greatly appreciated

thanks!

 

If the service 4wd light is on, that means that there are stored codes in the TCCM. The code(s) will give you some direction in terms of diagnosing the problem. A full feature scan tool capable of accessing the TCCM must be used.

You can trace out the wiring using the diagrams found in the NV236 Wiring & Diagnostic Information thread.

 

we replaced the transfer case motor (encoder motor) and the actuator under/near the battery.

now, when i start it, it starts in 2hi, then 30 seconds later, the 4lo light starts to blink and it switches back to 4lo.

i pulled the vacuum line on the driver's side near the fuse box, it seems as though this is now preventing it from actually switching to 4lo.

Will this harm anything? Taking it to the dealer in 4lo would be extremely painful.

thanks!

 

update: after further investigation, it appears as though it does go into 4lo with the vacuum line detached. might be an interesting trip to the dealer

 

What did you find out was causing this issue??

 

I am also interested in this... the same thing will happen to my blazer (2001) if I touch any of the 4WD buttons. It takes much random button pushing, rocking back and forth, and luck to get it out of 4-lo.