A/C Switch Fault (Active), Checksum Failure (Active), Defog Switch Fault (Active) & Washer Switch Fault (Active)

NOTE: All DTCs listed are diagnosed using this test procedure.

When Monitored:

A/C SWITCH FAULT (ACTIVE), DEFOG SWITCH FAULT (ACTIVE) & WASHER SWITCH FAULT (ACTIVE) - With ignition on.
CHECKSUM FAILURE (ACTIVE) - At every power-up (5 seconds after ignition is on).

Set Condition:

A/C SWITCH FAULT (ACTIVE) - This DTC will set if A/C On/Off Switch ("snowflake" button in A/C-Heater Control Module) stays closed for 10 minutes.
CHECKSUM FAILURE (ACTIVE) - This DTC will set if the calibrated check sum does not match the stored value.
DEFOG SWITCH FAULT (ACTIVE) - This DTC Will set if the Electric Back Light (EBL)/Rear Window Defogger Switch stays closed for 10 minutes.
WASHER SWITCH FAULT (ACTIVE) - This DTC Will set if the Rear Washer Switch stays closed for 10 minutes.

Possible Cause:

A/C-Heater Control Module.

CAUTION: Always turn ignition off before disconnecting or connecting any control module connector. Failure to do so could result in damage to control module.

NOTE: Ensure vehicle being tested has a fully charged battery. If it does not, false DTCs or error messages may occur.

NOTE: For component location, see appropriate illustration under COMPONENT LOCATIONS . For terminal identification, see appropriate illustration under CONNECTOR IDENTIFICATION . For circuit and wire color identification, see WIRING DIAGRAMS . For component removal and installation procedures, see appropriate component under REMOVAL & INSTALLATION .

Testing:

Replace A/C-Heater Control Module. Perform BODY VERIFICATION TEST under VERIFICATION TESTS.