I have a 94 S10 blazer which has given me headaches with the 4wd system. I would really appreciate any info for what to do. My blazer has 248,000 miles on it. It all started last year when the 4wd wouldn't work at all. I've tried replacing tccm module and disconnecting battery and tccm module to reset the 4wd but that didn't help. My 4wd hi light stays on all the time but nothing is engaged, transfer case etc. When I push the 4wd hi switch or 4wd lo you can hear the tccm module clicking. I've replaced the vacuum switch on t-case , all vacuum lines. Just to a point that I don't know what else to do PLEASE HELP.

 

It sounds more like the encoder motor than anything else you have changed. The encoder tells the TCCM what position the transfer case is in.

 

Ok thanks swartlkk for the info. I'll check into that and let you know what happens. Again I really appreciate the help.