hvac issues none of blend door motors move all new?

2007 GMC SIERRA

15,700 MILES • 4.8L • V8 • 4WD • AUTOMATIC

DUSTINISTRE

MEMBER
1 POST
FOLLOW

2007 GMC 1500 4x4 classic dual climate control auto none of the 4 motor that control air are working iv replaced all 4 motors and controller. controller comes on and can adjust fan speed and turn on and off compressor but will not go hot to cold or outside air to recirculate or from vent to defrost to floor.

Mar 23, 2025 at 5:17 AM

STRAILER

CERTIFIED EXPERT
53,855 POSTS

Hello,

I would check the HVAC BATT fuse in the fuse panel under the hood for power when the key is on. Also, there is a main ground (G200) for the controller which I would look at as well which is located at the right front corner of the HVAC module. Here are the wiring diagrams for the HVAC system so you can see how the system works. You can test the ground by unplugging the HVAC controller and this guide:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Check out the images (below). Let us know how it goes.

Images (Click to enlarge)

Mar 23, 2025 at 10:51 AM