B100F

B100F-MIX SWITCH REQUEST INPUT CIRCUIT/PERFORMANCE



Theory of Operation

The HVAC A/C Heater Control contains various switches and knobs that are used to change the systems operation. Many of the switches are momentary switches which are normally open or in the Off position and the status changes when the switch button or knob is pushed or turned. An active Diagnostic trouble Code (DTC) indicates that the switch is stuck in the On position. A stored DTC indicates that the switch was stuck in the On position for more than two minutes but has since returned to its normal state of Off.

- When Monitored:
With the ignition on.

- Set Condition:
If the Mix Mode Switch is stuck in the On position for more than two minutes. This DTC has a de-maturing time of one second. If the DTCs status changes from active to stored, the DTC will stay in memory for 100 ignition cycles.





1. INSPECT FOR OBJECT HOLDING SWITCH IN THE ON POSITION
1. Inspect the A/C Heater Control for an object or debris holding the Mix Mode Switch in the On position.

NOTE: Using the scan tool you can read the On/Off status of the control switch.

Is the Mix Mode Switch being held in or stuck On?

Yes

- Clean or repair the A/C Heater Control as necessary. If you are unable to clean the switch to where the switch can work properly, replace and program the A/C Heater Control.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Go To 2

2. A/C HEATER CONTROL
1. Turn the ignition on.
2. Using the scan tool, erase HVAC DTCs.
3. Turn the ignition off for ten seconds, and then turn the ignition on and wait a minimum of two minutes.
4. Using the scan tool, read HVAC DTCs.

Does the scan tool display this DTC as Active or is the status of the switch reading On?

Yes

- Replace and program the A/C Heater Control.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Replace and program the A/C Heater Control.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.