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2001 limited only blows thru ac vents

02-06-2017, 09:02 PM
I believe my ATC HVAC Mode actuator is shot, as air only blows out thru the AC vents, and not the floor or windshield vents. Does anyone know the easiest way to R&R this actuator?
I would sure appreciate any advice you can provide. The actuator is show in the figure(Item2)

02-07-2017, 09:43 AM
Most common failure is lack of vacuum supply- check the purple hose, if no vacuum, then look under hood at vacuum reservoir box for rotted, broken plastic vacuum lines- trace it all the way back to intake manifold source.

If vacuum is present, check the ATC vacuum manifold at entrance to solenoid box- behind glove box- it can get bad, turn to mush.

Tech II
02-09-2017, 03:51 PM
From the picture it looks to be driven by an electrical actuator....two or three 5.5mm screws hold it in......I have a small thumbwheel ratchet to get into tight areas...gears on these actuators break a lot...

11-23-2018, 12:37 PM
This problem was solved by taking it to a GM shop that charges reasonable rates. The mechanic got to the part by getting on his back on the drivers side floorboard, removing the black plastic shroud above the pedals and going up thru the bottom middle left part of the dash. I'm pretty sure he did it mostly by braille and his knowledge of what's under there, as it's pretty hard to see the actual part. He also mentioned that you have to take care not to disturb the position of the control arms/levers that the broken actuator moves, or reassembly will be much harder than necessary. Also, I'm not sure if a Tech II scanner is required for a relearn or not. But it wasn't too bad... I was charged ~$190 out the door, and that even included a refrigerant check and top-off.

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