05blkcpe

I seem to be having problems with my climate control in my 05 C6, when I try and switch from window defrost to heating or cooling out of the center vents nothing happens, it just continues blowing air onto the front window, has this happened to anyone? Is there any way to fix it? Thanks

JC13ZR1

Nobody ever responded> I am now having the same or similar issue.

RicK T

One response in 7 years, and it's another question!

JC13ZR1, please provide more detail of your symptoms and we may be able to assist. And I suggest you just start a new thread.

Unreal

The c6 climate control modules fail. I've replaced mine twice. It is becoming a more and more common issue as they get older.

JC13ZR1

I thought about starting a new thread, but anyway...

My 2013 ZR1 just started acting up. Auto seems to have no function. I can turn the system on and off, and increase fan speed but not decrease. I cannot change where the air comes out - currently on vent and also gets the windshield (which fogs it up here in Houston). If I hit recirculate that increases fan speed but not much else that I can tell. I can change temps on both sides but I am not sure it makes any difference.

RicK T

You have a mish-mash of symptoms that could be one thing or two. My guess would be the HVAC head unit in the dash (the thing you interact with). As mentioned above, it is a common failure item. Members have been able to find new and used ones in the C6 Parts Forum as well as ebay or elsewhere for less than dealer new price. New from dealer they are around $450 (ish). You could get the OBD HVAC codes read but most consumer grade readers don't do those, you would likely have to go to a dealer or other shop with a Tech II and dealers usually charge for reading codes but some don't. Changing the unit is a DIY job, about the same as changing the stereo head unit.

JC13ZR1

Thanks - that's what I thought would be the best bet. I ordered a new one on Amazon.com for $307.27 prime, 2 day delivery. I will receive today but I'll be out of town until Saturday so will try it out this weekend.

extrapilot

Have you tried disconnecting/reconnecting the battery? This sometimes resets the head unit..

JC13ZR1

that didn't help. Thanks!

Homer3D

I had a similar issue and this is what I did. Disconnected the battery for like 5 minutes. Reconnected, problem solved.

In fact this has happened to my 2013 twice so far and both times fixed by disconnecting the battery. Never once happened in my 2005 C6.

djsv810

Where and how did you get it repaired? What was the cost?

Unreal

Bought a new climate control unit, swapped it out. Was ~$350 I believe. Replaced it myself. Super easy, just pop center console out. Plenty of guides on that.

Boomer013

Mine just started doing this exact same thing! Fan speed will increase but not decrease, the modes wont change from vent to floor etc but a/c and everything works. Dealership said it was the climate control module, so ordered one and put it in tonight, same problems still occurring with the new unit.

So now I am not sure if the actuators are simply burned out and no power is going to them period but that doesn’t explain the fan speed. Anyone have additional possible resolutions for this? Thanks!

JC13ZR1

Control module did nothing for me. the shop that's working on it now is currently diagnosing mine. By the way it made my dash begin to bubble up around the defrost vents, so watch for that if you don't get it fixed soon. Did GM service diagnostics and changed the AC mode actuator and now it moves, but the mode valve is curled up or something so will be replacing the mode valve and the other three actuators, which means dash has to come out. Will let you know if that fixes it.

Boomer013

Thanks for the feedback! Hope you get it sorted out. I’m certain my issue is the same as yours and will need the same parts replaced. :-(

Tracy

Any updates to this situation? I have the same issue(s) described above, changed out the control unit with a re-manufactured unit from ASI, did the fuse pull.....no change. Not looking forward to pulling the dash apart, nor having the dealer do it for giant money and leaving lots of squeaky noises behind.

KyleMonaghan

Hey there Unreal! I'm brand new to the thread. Like the posts above, I'm also having problems with my climate control module. The fan speed won't come down after turning it up, and the mode door actuator tries to operate even when the car is off. I see you recommend replacing the HVAC control module. Why do you think this fix didn't work for several other members on this post? Also, is replacing the HVAC control module is simple as plug-and-play, or does it need to be calibrated with a scan tool? Thanks!

schizcat

So we jumped from 2010 to 2017 to 2021....this is one hell of a rehashed thread

To answer your question, yes its easy if you have patience and some working knowledge of cars. No, you dont need a scan tool to recalibrate it.

tennblkc6

sorry to bump this thread but I'm hoping some of the members that has experienced the ac blowing through the defrost will post their fixes.
mine was not blowing through the center vent so i disconnected the battery,, pulled all 3 fuses and let it sit for over an hour while i cleaned the garage. reconnected the battery..installed the fuses then cranked her up...ok..all is well and now blowing through all vents. shut her down and went back to cleaning. got through and went to move the car and same thing..blowing out defroster. did another long reset 3 more times and it didn't work.
does this sound like head unit.

USA1LBvert

I’ve been having similar issues for two years. Hvac basically has a mind of its own. A/c sometimes comes on full blast and won’t shut off. Sometimes it doesn’t come on when I want it too. Sometimes it comes out the defrost vents and sometimes it will come out all the vents. In the summer I have to make sure the temp is set to cold because it will decide to come on blowing hot air and it won’t let me adjust the temps. Crazy. I am in search of an hvac head unit hoping it will sure the issues.