Additional Clarification of HVAC Modules and Locations, Descriptions in SI

When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

Additional clarification of HVAC modules and locations descriptions in SI.

There are 4 HVAC control modules on this vehicle.

1. HVAC Control module - Located in front IP panel near radio. You can communicate with the HVAC control module via class II under heating and air conditioning.
2. HVAC Control Assembly - Front Auxiliary - (control head)-- Located above the rear view mirror. Cannot communicate on class II. Provides driver requests for rear operation via dedicated circuit inputs to HVAC Control Module-Auxiliary.
3. Rear Seat Audio controller (control head) - Located in the rear of center console, you can communicate with the RSA/HVAC module with the Tech 2 under Rear HVAC. Communicates via class II to other modules.
4. HVAC Control Module - Auxiliary (programmer). Located on the rear HVAC case behind quarter trim. Use document ID number 899666 to see illustration. You can communicate with the Auxiliary HVAC Control Module with the Tech 2 under Rear Aux. Climate Module. Receives requests via class II and discrete inputs. Provides direct output to rear HVAC control devices (actuators, blower module).

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.

03 CHEVROLET TAHOE, SUBURBAN

03 GMC YUKON, YUKON XL, DENALI

03 CADILLAC ESCALADE