My apologies if this has been answered a dozen times. I tried to search a few times to find similar topics.


My rear ac won’t blow warm/hot air. Front does just fine. Not exactly sure where to really start for diagnosis to be honest.

Any help would be appreciated.

2017 Suburban Premier if trim package is useful.

 

Do you mean that the rear blower fan does not work or blow air? Must start with the basics.

 

I am reading this as saying that your rear AC blows COLD air, just no heat back there. The rear HVAC in a Suburban is based on an auxiliary HVAC module, in the right rear of the cargo compartment behind the back seat, at least through year model 2013 - the most recent I see on the charm.li website. That is where it was in my 2003 Yukon (GMC version of the Suburban). Problems *I think* it could be:

• Blend door actuator (electrically controlled)
• Blend door linkage
• Auxiliary heater core

You will need to remove the rear cover trim panel to access it.

This may give you an idea, its for the 2013 Suburban:

https://charm.li/Chevy%20Truck/2013/...0Wheelbase%29/

I am not telling you to remove it - just showing you where it is located with that diagram.

Even though it is for the 2013, the testing and diagnosis section here may be of use:

https://charm.li/Chevy%20Truck/2013/...d%20Diagnosis/

A real simple thing though to check is your coolant levels under the hood. If you are low at all on engine coolant, there may be insufficient to flow to that rear heater core. Check your radiator and coolant overflow reservoir levels before you do anything else.

 

Blower fan works, I get cold air no matter the setting.

 

Thank you for the diagrams. It’s really appreciated. I’ll check my coolant levels first then move into the cover if not resolved.

 

You can also feel the coolant lines lines as they run from under the hood down the passenger side frame - see if they get nice and hot will show you at least have coolant going to the rear core