02 Dak 4.7,5spd. Lite came on along with no door lock at speed etc. DRB shows no comm. w/tranfer case module and no codes in other modules. Any ideas? Power and grd appear good at this point. How is the transfer case module tied to the timer module,door locks etc? Any help is appreciated!

the body control module prob controls the t case module, over a network...if you have a drb you should be able to activate the modules, if its a comm error, could be a bad module or a wiring issue. there is so much computer crap in vehicles today its unreal!

Maybe a broken wire or two in the door jamb? Possible with other problems coming at the same time.

If the truck has a central timer module, located in the drivers kick panel, unplug all three connectors and plug them back in after a few minutes. If the door locks come back to life, the module is no good. Common failure. Around $200. The failed module will also turn on the light.

The CTM is a junction module that has several circuits going thru it from many non related systems. If you can find a skematic on line you can veiw the inputs and outputs.

I think it keeps you from trashing truck if you accidently spin the 4x4 selector switch clockwise(which is 4x4 low loc mode) when driving down highway in 2wd mode. I did that at night once, thinking without looking, that I was twisting the a/c fan switch on. Realized it immediately, but nothing happened. Maybe computers are a good thing......sometimes.