hi all im new and have a 99 blazer..the trouble im having is at first the 4wd drive wouldnt engage, the push button lights would just blink..i found a vacuum line going to that thing under the battery cut so i replaced it.. now the 4wd drive is engaged and wont disengage..just blinks once again..where should i go next...oh yeah.you can hear the shift motor running but its apparently not doing anything

 

Classic questions... How many buttons are on the dash (3-button = NV233 / 4-button = NV236)? Have you pulled the codes? The NV233 can be done easily as described in the tech article section. The NV236 requires a scan tool capable of accessing the TCCM (transfer case control module).

Check out the Tech Article (DIY) section for more helpful 4wd related threads.

 

i have 4 buttons...auto 4wd, 2hi 4hi 4lo and no i havent gotten codes yet but i can go do that if that would help in troubleshooting

 

Is the service 4wd light on in the dash? If so, getting the codes read from the TCCM will help give direction to the diagnosis.

Try disconnecting the vacuum hose from the vacuum solenoid on the firewall and see if it will shift into 2wd. If it does, then the solenoid might be bad or the lines may be on backwards.

 

i pull the vacuum hose off but it wouldnt shift back to 2hi, but now the thing wont engage back into 4hi..lol..its possessed

 

Pull the passenger side kick panel & take a look at the electrical connections on the TCCM. While you have things apart, measure the resistance of the switch in the dash at the switch as well as at the TCCM. The wiring diagram & resistance values can be found in the NV236 tech article.

 

thats out of my league..im not much of a mechanic..