Control Assembly: Testing and Inspection

The control switch and timer circuit may be tested in the vehicle with or
without a DRB III scan tool.

TESTING WITH THE DRB III SCAN TOOL
If using the DRB III scan tool, refer to the proper Body Diagnostic Procedures.

TESTING WITHOUT THE DRB III SCAN TOOL

HVAC Control Module Connectors:

1. Remove the control switch from console and do not disconnect control switch.
2. Using a ohmmeter, check leads between Pins 5 and 8 of the 8-way connector. Depress the rear window defogger button and the resistance reading should be 500 - 520 ohms. If not OK, replace HVAC. If OK, check:
- Rear window relay (EBL)
- Blown fuse
- Cut wire
- Poor ground
- Poor connection
- Defective BCM
- Bulkhead connector inoperative
Refer to Wiring Diagrams for circuit information.