Test D: The Heating Ventilation Air Conditioning (HVAC) Module Does Not Respond To The Scan Tool

PINPOINT TEST D: THE HEATING VENTILATION AIR CONDITIONING (HVAC) MODULE DOES NOT RESPOND TO THE SCAN TOOL

Normal Operation
The HVAC module communicates with the scan tool through the UBP communication network. Circuit 1906 (VT) provides the network connection to the HVAC module. The HVAC module shares the UBP network with the instrument cluster (IC), the vehicle security module (VSM) (if equipped) and the driver seat module (DSM) (if equipped). Voltage for the HVAC module is provided by circuits 296 (WH/VT) and 729 (RD/WH). Circuit 875 (BK/LB) provides ground.

This pinpoint is intended to diagnose the following:
- Fuses
- Wiring, terminals or connectors
- HVAC module

D1-D3:

D3-D4: