I have a 2000 s10 blazer with 4wd auto 2hi 4hi 4lo light is flashing but 4wd won't engage mechanic said there was no communication at the tcm and it could be the body control module or the transfer case module . I replaced the tcm (used part) no change. Any ideas before i replace the bcm any.


Need 4wd before the winter thanks

 

BCM has nothing to do with the 4wd system.

Clean all of the connections at the TCCM, switch, and encoder motor on the side of the transfer case.

Then test the switch for proper resistance values. Search for "nv236+resistance" and you should turn up the proper information. You can also search for "nv236" and get even more threads. Remove the quotes in both cases when you type that into the search tool.

 

Thanks for the info i'll check it out and let you know how it went

 

Try stopping and putting the truck in Neutral before you hit the 4wd button and/or backing up (slowly) a bit after you press the 4wd button (especially 4lo).

 

Tried putting it in neutral that didn't work but 4lo worked when i put it in reverse but i couldn't switch it back to 2 hi drove around tried reverse again still wouldn't switch. Finally tried neutral again and it switched to 2hi the tccm is clicking only when 4wd actual switches any ideas?