To begin, yes i have read thru many posts close to mine but no luck yet. I will start at beginning and run thru all i have so far. I have an 05 silverado and original issue was when making hard turns in driveway and parking lots, the truck felt like 4wd was locked in, although switch indicated its in 2hi. Well 3 days later 4wd switch didn't have any lights on and "service 4wd" popped up on cluster. Well i started at switch and tested the ohms and all was good except Auto4wd, got new switch and same deal. Tested it and it ohm'd exactly the same as old one. So before i spend more $$ random replacing, i paid a guy i know with a tech 2 scanner and he gave DTC: C0321. Just cant remember which one exactly and he done cleared his scanner. But along the lines of circuit malfunction. He said his best idea was a wire issue. So i start by cleaning grounds at drivers cab bushing. No change. So i test the 12v (orange), ground (black) and "low volt signal wire" (red) at the connector for encoder motor. 12v and ground was fine but the "red" was not giving any power. So i followed red wire thru harness, testing in several spot, as i have heard of pinching issues, and ended at the tcc module. At the module black 4 pin connector, again i tested 12v and ground, fine. But still nothing from the red. I went and got a used module from truck with blown engine. Put it in and still having same problem. Once again i test red wire but this "new used" module is giving 1.3v thru it from module all the way down to encoder motor connector. Have read its suppose to be 5v thru that wire. Put my old one back in and its testing 1.3v exactly also. Im at a stand still and not sure what to try next that doesn't cost me a encoder motor without certainty. Also i must add, while hooked to tech2 scanner, he was able to manually switch it between 4hi,4lo and 2hi so i really don't believe the issue is in the actuator on the differential, since it was locking into gears and operating actuator. I have removed 4wd driveshaft to try and test encoder wires closer to housing.