Heater blowing cold air

Hello,

It sounds like you have temperature blend door actuator that is out and needs to be replaced. Here is a guide that has a video showing you how to fix the problem:

https://www.2carpros.com/articles/replace-blend-door-motor

Make sure hot coolant is getting to the heater core by checking the heater hoses in the engine compartment. Make sure the blend doors and temperature controls in the heater box are functioning properly.

Here are the diagrams to change the temperature air door motor (below).

Please let us know what you find.

Cheers, Ken

Check the air blend door and actuator, if okay could be coming from the HVAC control module itself.

Have you tried back flushing the heater core? You can try also running the vehicle and seeing if you have hot going into the heater core and seeing if you have hot coming out. If you do not the heater core is either plugged or faulty.

Check the operation of the blend door on the passenger side below the glove-box. Verify the HVAC controller is sending commands to the blend door actuator. If the coolant level is correct, the thermostat opens and closes as it should, and the blend door works, the heater core could have debris. Does it have Dex-Cool that is older than three years in it?

Hey Shakazooloo8,

This is a common problem, you have a blend door actuator that is out and needs replacement. Here is a guide that will help you:

https://www.2carpros.com/articles/replace-blend-door-motor

Please let us know happens so it will help others.

Best, Ken

Door actuator on the drivers side may be bad as it controls the blend door. Common failure.

Roy

First check for any fuses under the hood or inside that blew from the surge when reconnecting the new battery. If they are all okay, you got caught by one of GM's many tricks to get you to go back to the dealer. With newer vehicles you must never disconnect the battery. Use some type of memory saver to keep all the many computers' memory circuits alive. A heating control system failure is not one of the ways these vehicles normally act so I am hoping you find a blown fuse, but if not, the dealer will have to unlock or reprogram that computer.