B1012

B1012-DEFROST SWITCH REQUEST INPUT CIRCUIT/PERFORMANCE (ATC & MTC)

For a complete wiring diagram REFER to DIAGRAMS/ELECTRICAL .

Theory of Operation


The switch input changes when the switch is pushed down. A stored DTC indicates that the defrost switch was stuck in a pushed position for more than 10 minutes, but has since returned to its normal state. An active DTC indicates that the defrost switch is stuck in a pushed position.


- When Monitored:
With the ignition on.

- Set Condition:
If the defrost switch is detected in a pushed position for more than 10 minutes.






Diagnostic Test


1. INSPECT THE A/C HEATER CONTROL FOR DAMAGE
Inspect the A/C Heater Control for damage.
Is the A/C Heater Control damaged?

Yes


- Replace the A/C Heater Control.
- Replace the A/C Heater Control.
- Perform HVAC VERIFICATION TEST - VER 1.HVAC Verification Test.


No


- Go To 2


2. INSPECT FOR OBJECT OR SUBSTANCE CAUSING THE DEFROST SWITCH TO STAY OR STICK IN A PUSHED POSITION
Inspect the A/C Heater Control for anything that would cause the defrost switch to stay or stick in a pushed position.
Is anything present that would cause the defrost switch to stay or stick in a pushed position?

Yes


- Repair as necessary.
- Replace the A/C Heater Control.
- Perform HVAC VERIFICATION TEST - VER 1.HVAC Verification Test.


No


- Go To 3


3. CHECK FOR NORMAL DEFROST SWITCH & STATUS INDICATOR FUNCTION
Turn the ignition on.
Press the defrost switch.
Does the defrost status indicator illuminate?

Yes


- Go To 4


No


- Replace the A/C Heater Control.
- Replace the A/C Heater Control.
- Perform HVAC VERIFICATION TEST - VER 1.HVAC Verification Test.


4. VERIFY THAT DTC IS STILL ACTIVE
With the scan tool, erase HVAC DTCs.
Turn the ignition off, wait 10 seconds, and then turn the ignition on. Wait 10 minutes before proceeding.
With the scan tool, read HVAC DTCs.
Does the scan tool display this DTC?

Yes


- Replace the A/C Heater Control.
- Replace the A/C Heater Control.
- Perform HVAC VERIFICATION TEST - VER 1.HVAC Verification Test.


No


- Replace the A/C Heater Control.
- Perform HVAC VERIFICATION TEST - VER 1.HVAC Verification Test.