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04 Chevy 1500 with manual dual zone climate control. It's not the blend door actuator, had 4 swapped in do the same thing. Actuator will go straight to heat when plugged in. You can stick the actuators in another truck and move them to cold, dis connect and put back in the problem truck and straight to heat it goes.
It's just the drivers actuator that has this problem. The driver and passenger temp control detents show to be working on scan tool. The drivers actuator count stays at 0 no matter what. Passenger count works as normal.
Drivers actuator plug has 5v, and 2.5v with key off, key on has those plus 12v. Also has ground and the last pin that shows nothing as far as I can tell. Guessing it has to do with the counts.
From what I understand the 2.5v pin changes to move the blend door. It stays the same all the time. Am I looking at a bad a/c control unit or what?
I tracked a similar issue down to a poor connection In the i/p connectors behind the passenger side little i/p trim panel that ya have to open the door to get to. Simply disconnect all the connectors behind that panel and plug them back in. I fixed 2 chevys with that same problem...
Drivers actuator plug has 5v, and 2.5v with key off, key on has those plus 12v. Also has ground and the last pin that shows nothing as far as I can tell. Guessing it has to do with the counts.
Not sure what you're testing with but it sounds like you've got an open on the position feedback wire. It's 5V pulldown so you should see ~5V on it unplugged with a decent DMM. The IP connector ptebo1 mentioned is a good spot for further testing.
I'll see if I can find a cut wire further in the dash. There wasn't a chaffed wire at the glove box brace I've read about. There was a mouse nest on top of the HVAC box but no visible wires chewed.
Figured it out. The a/c forgot how to a/c basically. Pulled the fuse and put the knobs in the reset positions. Seems to be working for now and the counts show up on the scanner.
