Hey all,

The car is a 2013 base model.

I recently noticed that the AC system in my car is behaving...strangely. I typically leave it set to automatic and adjust the temperature to suit. As of last week, the vent control no longer functions; when you switch to, say, the floor vents, the air still comes out of the dash vents exclusively. Which means no defrost.

Also, the fan speed will sometimes not automatically change. It can still be changed manually, fortunately.

Temperature control does appear to work normally.

I have already tried removing/replacing all fuses/relays related to the HVAC system, and the issue hasn't changed.

What's my next step? I figure disconnecting the negative battery post for an hour is a good starting point - maybe it'll reset something. I'll also pull the dash panel and make sure all the wiring is firmly connected to the control panel.

What else could be the problem? I figure there are a few motors required to change the airflow path, so it's unlikely that ALL of them went out at once. Thus, assuming it's not just a computer glitch or a wiring issue, the problem is most likely a bad control unit, right?

Thoughts, comments, etc?

Thanks!

 

Only thing I can help you with is to remind you that you'll have to reset the window indexing when you hook the battery back up again.

 

There are several motors/roller flaps behind the dash that control where the air comes out, they occasionally fail but usually not this soon.
You might get lucky and it's something (relatively) easy like the electronic controller. If it's a motor/flap, labor is very high to replace.

I'd start out at a shop or dealer that can check for any set codes.

 

pulled the climate control unit and checked the wire connections. all was good there. The actuators don't seem to be getting any signal to move at all (pulled the glove box and put my hand on them and didn't feel any clicking or anything when changing the modes so I assume they are good...mostly because they look to be a bear to replace). Had the battery disconnected for a while and that didn't resolve anything either.

Also, interestingly, once I manually adjust the fan speed to a setting, it will no longer lower the speed down for that ignition cycle....so I think I'm going to assume the control unit is bad. Car is out of warranty so if that's the case I'm looking at a $300-500 part lol. At least I won't have to pay anyone to replace it. I can actually order through amazon, which means I can return it if I later determine that the control unit isn't the issue. Kind of an illogical method, but as they say "try the easiest fix first".

Fortunately the HVAC does still work; even though it is a bit handicapped it's not like I'm going to freeze or melt. For now, I'll see about having a code check done. Not sure if my flashscan can read anything from the BCM or if it's limited to powertrain codes. One of these days I'll have to get myself a tech 2...

 

My 2013 exhibited similar behavior when I got it April 2015, with only 7k miles. The dealer replaced the HVAC head unit in the dash and actuator motor under the dash and no issues since.

 

good to know I'm not alone.

In other news, how did you find a 2013 with only 7k after 2 years?! I bought mine new in July '13 and have 47k......I think I might enjoy it too much lol

 

A friend just got a 2013 GS Heritage convertible two weeks ago with only 3800 miles! Seems alot of people buy Vettes to look at, not drive.

I'd buy a TV instead!

 

Appears to be either a malfunctioning head unit or a faulty actuator. If you have access to a scan tool you could check to see if any codes have been thrown. Many auto parts stores (Auto Zone, O'Riley's, etc.) will pull codes for you at no charge. Of course, your friendly Chevy dealer will do that for you too; but for a fee.

The head unit is plug and play and about a 5 minute job to change out. The actuators are an entirely different story; they are buried in the dash and a real PITA to get to. Good luck.