Transfer Case Control Module Symptoms, Tip

Got a 98, 4wd with 233c transfer case, 3 button. Symptoms were, 2hi,4hi/4lo lights flashing when driving, but 4wd worked as advertised. Finally, no lights on start up, and 4wd did nothing. Searched the posts here, and tried the unplug/plug the TCCM with key on, no change. Figured, what the Heck. Tried it again with engine running. TCCM worked like it was suppose to. Once I turned the blazer off and restart, no 4wd. Found a TCCM at local yard, now it works like advertised. Figured this might help someone.

The TCCM (transfer case control module) and the encoder motor, located on the transfer case itself, are the two most biggest problems when the 4x4 system begins to malfunction. Unfortunatly both can be quite expensive to replace.

Thanks for letting everyone know what fixxed it! :bigthumb:

my 4wd Hi isn't engaging, but 4Lo does (just put in a new encoder motor and vac actuator). when I push 4Hi the lights on the 3-button selector switch flash about 5 times then it goes back to 2Hi. i don't get any buttons flashing randomly when i'm driving...only when i try to engage 4Hi. could this be a faulty TCCM? how do I check to see if the TCCM is working properly?

my 4wd Hi isn't engaging, but 4Lo does (just put in a new encoder motor and vac actuator). when I push 4Hi the lights on the 3-button selector switch flash about 5 times then it goes back to 2Hi. i don't get any buttons flashing randomly when i'm driving...only when i try to engage 4Hi. could this be a faulty TCCM? how do I check to see if the TCCM is working properly?

The only test I have heard of is ground out pin 13 on the data port and turn on the key and count the light flashing. Someone here can give you the meanings. Or when I fixed mine, I checked voltage at the switch, fuses then the TCCM. But it looks like you have good voltage.