Control Module HVAC: Testing and Inspection

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

Testing with scan tool
If using the scan tool, refer to the proper Body Diagnostic Procedures.

Testing without scan tool

HVAC Control Module Connectors:

1. Remove the control switch from console and disconnect control switch.
2. Using a ohmmeter, check leads between Pins 5 and 8 of the 8-Way connector. Turn the control module to each position shown on Control Module Test table. The resistance reading should be within the specifications shown. If not OK, replace the control module. If OK, check:
- Blown fuse
- Cut wire
- Poor ground
- Poor connection
- Defective BCM
- Bulkhead connector inoperative.

Control Module Test Table
SWITCH POSITION = OHM RANGE
Panel = 828 to 856 ohms
Bi-Level = 1.279 to 1.315 K ohms
Floor = 2.302 to 2.358 K ohms
Mix = 5.202 to 5.318 K ohms
Defrost = 99.5 to 101.5K ohms