B1021

B1021-BLOWER SPEED UP SWITCH REQUEST INPUT CIRCUIT/PERFORMANCE (ATC)

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 blower speed up 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 blower speed up switch is stuck in a pushed position.


- When Monitored:
With the ignition on.

- Set Condition:
If the blower speed up 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 BLOWER SPEED UP SWITCH TO STAY OR STICK IN A PUSHED POSITION
Inspect the A/C Heater Control for anything that would cause the blower speed up switch to stay or stick in a pushed position.
Is anything present that would cause the Blower Speed Up 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 BLOWER SPEED UP SWITCH & STATUS INDICATOR FUNCTION
Turn the ignition on.
Turn the A/C Heater Control on.
While observing the A/C Heater Control display, press the blower speed down switch several times, then press the blower speed up switch several times.
Does the blower speed display in the A/C Heater Control change according to the position of the blower speed switch?

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.