2009 Yukon - AC not blowing in middle seat vents.

[Mr_Greg]

Hi everyone,
I have a 2009 Yukon SLT. The AC vents on the ceiling for the middle seats are not blowing any air. The front AC and the AC to the 3rd row works just fine. It is just the middle seat vents that are not getting any air at all. Any idea on where to start troubleshooting this issue?

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

I cannot personally assist you with your issue, but other members of this Forum much more knowledgeable than me in this area will chime in. @swathdiver

 

[swathdiver]

Hi everyone,
I have a 2009 Yukon SLT. The AC vents on the ceiling for the middle seats are not blowing any air. The front AC and the AC to the 3rd row works just fine. It is just the middle seat vents that are not getting any air at all. Any idea on where to start troubleshooting this issue?

Open the vents over the middle row!

I'm not exactly sure what's wrong here. The auxiliary mode actuator controls where air flows for the rear AC. It does not make sense to me that the 2nd row is not getting any air and the 3rd row vents are. I'm not an expert on how the system works. I wonder if a critter has created a nest inside possibly and blocked the flow or air?

A Tech-2 or similar tool can test the actuator and see the internal BCM codes to see if the actuator failed or got stuck.

The rear AC is on the right side behind the RR wheel well and under that panel below the window of course. The rear trim above and below the door has to come off as well as the trim on the RR door on the back and floor to pull the panel. It's best to look at the shop manual photos if you are going to tackle this. We replaced those two actuators recently ourselves.

 

[mikez71]

By middle vents, do you mean the roof vents? Then it could be the mode is not changing and not blowing to the roof?

All relevant info above!

Here's a pic... Actuators are behind unit most? years.
Loosen a few screws (base of evap case?) and one screw holds the top, then you can tilt the unit inwards to reach actuators behind..
I removed the middle duct piece and temp sensor you can see them still installed in the pic. May have also had to unplug some wiring to get the harness out of the way..