Alright guys, back again. My blazers 4x4 is a complete pain in the ***. As soon as i found out my 4wd wasn't working i troubleshooted (troubleshot?) the crap out of it. The first thing i did was replace the vacuum actuator and the cable and it still didn't work. Next I replaced the vacuum switch on the transfer case and wouldnt you know, the thing was saturated with oil and my 4wd worked like a charm. I get in my car to go to work today and i notice that none of my lights were working (2hi, 4hi, 4lo.) When i put it in neutral i can hear clicking but nothing happens. the 4hi and 4lo lights blink about 6 times but nothing shifts. sometimes they stay lit, so i hopped down and wiggled the front drive shaft and it moved freely. I'm afraid the transfer case is shot, but before i go about replacing it i want to get some second opinions on it..

Tl;dr
4 hi and 4lo blink about 5 or 6 times
doesnt shift into 4wd
no lights are on
afraid its transfer case
help

 

What year? Did you replace the vacuum lines, or at least clean the oil out of them? Oil in the lines can prevent mode and range shifts.


If you can't hear the transfer case shift, there might be corrosion on the TCCM connector, a bad encoder motor, bad circuit, bad dash switch etc.

 

It's a 95. As of an hour or two ago the 2hi light was on. I can only get it to do anything when I throw it in neutral. I hit the button it makes a click sounds like a turn signal. Then the 4hi and 4 lo click a few times and go back to 2hi. Or both stay on. I shot some compressed air through the lines when I replaced the vacuum switch.

 

Sounds like the encoder is not working.


95 will have one of two different connectors under the dash. If you have the OBDI ALDL connector under the dash, jumper pins "J" & "A" turn the ignition to the RUN position, and read the flashes on the lights in the 4WD switch.








The error codes are:
1 - RAM Standby Power Fault
2 - Encoder Fault
3 - TCCM Motor circuit
4 - RAM/ROM failure

1- Standby power fault: This code is set if the TCCM loses its constant battery voltage feed: disconnecting the battery, blown fuse, etc.

2 - Encoder fault: Each time the transfer case shifter position moves, the TCCM checks the encoder readings during the shift. If the encoder can't or doesn't shift the case, it will set this code.

3 – TCCM (Transfer Case Control Module) motor circuit.
Possible causes:
1. Open or shorted circuit between encoder motor and TCCM.
2. Short/open connection in the motor itself
3. Malfunctioning motor relay

4 - RAM/ROM failure: Internal software failure. Pull the TCCM fuse for 3 mins. Then replace it, and cycle the ignition from off to run 5 times. Then re-check the codes. If code 4 still is present, then the TCCM must be replaced.