Thank you in advance for the help.

My A/C has been running perfectly during the summer. Recently, I noticed that I started receiving A/C from the middle vents as well as the lower vents even though lower wasnt selected on the digital controls. That issue cleared itself up and now it is running fine again.

However, I just started getting B0363H for the left actuator. I cleared the code and I heard the actuator cycle but the code came back again as an H. I also tried removing the HVAC fuse to attempt to reset but the code came back again. I actually had the left actuator replaced by the dealer about 5 years ago.

Now that the weather has turned cold, today I turned off the AC (which was perfectly cold ie no refrigerent issues) and raised the temp for heat. However, there is barely any air coming out of the middle main vent even with the fan turned all the way up...but the passenger side blows fairly hard but the temp on the passenger side is slightly cooler.

I am wondering if these symptoms sound like a broken actuator? I find it hard to believe that it would break again in such a short amount of time since it was a GM part and the car is barely driven. Would a failed actuator cause there to be no heat out the middle vent but the ac runs normal?

Are there any more tests I should do to narrow the issue down?

thank you

 

Could be a lack of vacuum for the hvac controls.

 

This would be my first suspicion as well. The blend doors control temperature, but the vacuum actuators control direction and flow. Dual control system, yes? Are you running in auto mode, or directing flow with the mode button? The dual control system does a bunch of things on its own -- I tend to think it does so regardless of which mode is selected.

 

Where exactly is this hose? I’m having similar issues with the vents, you hear air blowing and nothing coming out.
sorry to hack your thread. Ty

 

You seem to like high jacking threads, but the vacuum source for the hvac controls comes from the back of the intake manifold there is an accumulator before the vacuum line enters the interior of the car.

 

Wanted to give an update on this issue...I pulled the #27 fuse for the HVAC and waited about 10 minutes. This allowed the actuators to reindex and to my surprise has (so far, knock on wood) fixed my issue ie the code is no longer coming back after several drives of the car. As far as the other issue of the momentary air out of all vents that has not occurred again either. Although I suppose that may be a different issue ie the vacuum line that goes to the passenger side fender. I will keep an eye on things and report back any changes. thanks for the help!

 

I have experienced the same problem, but found out that as soon as I drive the car the vents start operating correctly.