Test 10A - No Response From HVAC Control Module
NOTE:
For connector terminal identification see CONNECTOR IDENTIFICATION
. For wiring diagrams, see WIRING DIAGRAMS
. Perform VERIFICATION TEST VER-1A
after each repair.
CAUTION:
Always turn ignition off prior to disconnecting any module connector.
- Turn ignition off. Disconnect HVAC control module connector. HVAC control module is part of heater-A/C control head. Using an external ohmmeter, measure resistance between HVAC control module connector terminal No. 21 (Black/Light Green wire) and ground. If resistance is 5 ohms or more, repair open Black/Light Green wire. If resistance is less than 5 ohms, go to next step.
- Turn ignition on. Using an external voltmeter, measure voltage between ground and HVAC control module connector terminal No. 10 (Brown/Pink wire). If voltage is 10 volts or less, repair open Brown/Pink wire. If voltage is more than 10 volts, go to next step.
- Connect jumper wire between ground and HVAC control module connector terminal No. 14 (Violet/Brown wire). Turn ignition on. Using scan tool, select BODY, BODY COMPUTER, then SYSTEM TEST. Perform CCD BUS test. If scan tool does not display BUS SHORT TO GROUND, repair open Violet/Brown wire. If scan tool displays BUS SHORT TO GROUND, go to next step.
- Move jumper wire to HVAC control module connector terminal No. 16 (White/Black wire). Perform CCD BUS test. If scan tool does not display BUS SHORT TO GROUND, repair open White/Black wire. If scan tool displays BUS SHORT TO GROUND, replace HVAC control module.