My transfer case control module has a problem that i cant seem to diagnose. The old tccm would light up the 4 button switch..i tried to push 4wd and it just blinked for a few seconds and defaulted back to 2 wheel drive. i replaced the tccm and the 4 button switch. i dont have any fuses blown. i disconnected the battery and reconnected and now my service 4wd light does not come on at all and i have no power to the switch. i bought a replacement 4 pin connector for the tccm but the wire gauge doesnt seem to be the same as the wires coming from the truck from rock auto. i even switched both black wires around and still no power to the switch or a service 4wd light as if it doesnt recognize it at all. Im lost as to what to do next. cold and snow is starting to hit here in michigan and anyone who owns a blazer knows you gotta have 4wd to make it. please answer in full detail how to check problems like im a complete dummy. pictures would help as well. im not a mechanic but i can make my way through if im guided properly. also, the service engine light comes on but i feel its unrelated. thanks in advance for any help you can give me. dont have money to have a dealer look at it.

 

You are pretty much going to have to dig into the wiring and ohm out each one. It would have been nice to get the TCCM codes while the service 4wd light was on. It isn't there just to look demeaning... It means the TCCM was trying to tell you what was wrong with it.

Were the parts you installed new? Were they proper parts for your truck? There were a few TCCM for the NV236 transfer case and not all of them interchange. It should have had the same color connector on the TCCM itself as the one you took out.

The wiring information is in the NV236 Tech Article (DIY) section post (check out the index link in my signature below).