AC temp control on passenger side does not work on 2001 GMC Sierra 2500 HD

passenger side air is hot no matter where control is set.

Asked by for the 2001 GMC Sierra 2500 HD
You may have a failed temperature door actuator for the passenger side of your 2001 GMC Sierra. Fault codes stored in the AC control module would help to confirm this. You will need a scan tool to access these fault codes.