A different HVAC problem

[ts684]

2004 I-6 SWB manual HVAC control. Everything worked correctly but I was really getting annoyed at having almost all lights on the control head out. Tried to take it
apart but could not get the slider knobs off and almost destroyed them. Ordered a new Dorman? unit from Parts Geek, but got busy with life and didn't try to install
for a few weeks. After installation, there was a programming procedure to follow with included instructions. Well I followed the wrong directions and had hot air coming
out instead of cold and vice versa. Disconnected battery, waited a bit, reconnected and reprogrammed. Now hot and cold working properly. All Good? Not so fast.
Now there is no relationship between the control knob setting and which vents air is coming out of. Starting full CCL, on dash vent position, air comes out of floor vents.
Turning CL to floor position more and more air comes out of dash vents. Continuing CL, air starts coming out of defrost vents, but never stops coming out of dash vents.
Air comes out of side window defrost vents only when control is in dash position with air coming out of floor vents. AAARRRGGGGHHH!!!! I could live with this but it
is really annoying. I did try pulling fuses, disconnecting the batery, opening and closing door, and everything else I could find in other posts. Please note that everything
worked properly before I installed the new unit. Any suggestions? Get a used unit from a U-Pull It and hope lights work maybe?

 

[Mooseman]

Have you tried to do a system reset by pulling the HVAC-B fuse? Just pull it for 30 seconds, put it back in, turn the key to RUN but don't start. Let it do its thing while it relearns the actuators.

Not sure about the manual systems but the auto ones, if you get a new one, it has to be programmed by a dealer or someone with a Tech 2. It may need to be programmed.

 

[Reprise]

The other thing I was thinking of was - what was the position of the controls on the old module you pulled out? It may be that the mode actuator was in a different function than what you started out with on the new one.

Pull the HVAC-B fuse, as Mooseman suggested, and let the system recalibrate itself.

If that doesn't work, put the old one back in temporarily, and see if it realigns with the mode settings properly.

If it does - record the positions, and install the new one in the exact same mode. (you may need to do a second HVAC reset to get the old one sync'd again.)​

If it doesn't - you'll probably need to have someone with a GM diagnostic tool (Tech 2) connect to your vehicle and take a look at the HVAC programming.​

I've heard that when replacing the radio in an amplified (Bose) system, that the balance / fader settings are supposed to be set to 50/50 f/r, and 0 bias l/r - *before* removing the old radio. If not, your new head unit will never get those settings quite right (apparently, the fade / balance settings are retained - *in the amp*) Might be something similar for the manual HVAC - ?

 

[ts684]

Did pull fuse, after replacing and turning key to on, head a lot of movement going on, but still no luck. Tried this several times. Lucky I didn't throw the old unit out,. Thought about temporarily replacing but didn't get around to it yet.

 

[Sparky]

Yeah put the old one back in and see if it behaves normally. If it does, then I'd be seeing what the return policy is on the new one because something isn't right with it.