2011 GMC Sierra defrost not working properly

This problem is with all pickup truck-based GMC vehicles in the 1500-3500 series from 2010 to present. Margaret in our Ask a Mechanic forums brought this issue up with her 2011 GMC.

Big Block 409 quickly answered by posting a service bulletin (TSB 06-01-38-003), which deals with several air conditioning and defrost problems, including this one.

Pinboard (MacAaron)

Leave a Reply

Your email address will not be published.