Single-Z0ne

B1049-FLOOR/DEFROST MODE DOOR CONTROL CIRCUIT OPEN (SINGLE-ZONE)







Theory of Operation

The A/C Heater Control drives the Mode Door 2 (Defrost to Floor) Actuator via the (C801) Mode Door 2 Driver circuit and the (C34) Common Door Driver circuit. All of the door actuators share the (C34) Common Door Driver circuit. Inside the A/C Heater Control, each door actuator has its own unique driver, but all share a single common door driver circuit. Due to the shared circuitry similar Diagnostic trouble Codes (DTCs) can set at the same time for multiple actuators depending upon the location of the open circuit and the direction the actuator is moving when the open is present.

- When Monitored:
During actuator calibration.

- Set Condition:
If the Mode Door 2 (Defrost to Floor) Actuator's electrical circuit is open. This DTC has a maturing time of five seconds and a de-maturing time of 10 seconds. If the DTCs status changes from active to stored it will stay in memory for 100 ignition cycles.





NOTE: This DTC must be active for the results of this test to be valid. Do not perform this test if this DTC is stored. Perform the HVAC System Test HVAC System Test for stored DTC test procedures.

1. CHECK FOR ACTIVE CONTROL CIRCUIT/PERFORMANCE DTCs
1. Turn the ignition on.
2. With the scan tool, read active HVAC DTCs.

Does the scan tool display any active CONTROL CIRCUIT/PERFORMANCE DTCs?

Yes

- Testing and Inspection to diagnose and repair the DTCs.

No

- Go To 2

2. CHECK MODE DOOR 2 (DEFROST TO FLOOR) ACTUATOR CIRCUIT RESISTANCE




1. Turn the ignition off.
2. Disconnect the A/C Heater Control C1 harness connector.
3. Measure the resistance between the (C801) Mode Door 2 Driver circuit and the (C34) Common Door Driver circuit in the A/C Heater Control C1 harness connector.

Is the resistance above 70 Ohms?

Yes

- Go To 3

No

- Replace the A/C Heater Control.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

3. CHECK (C801) MODE DOOR 2 DRIVER CIRCUIT FOR AN OPEN




1. Disconnect the Mode Door 2 (Defrost to Floor) Actuator harness connector.
2. Measure the resistance of the (C801) Mode Door 2 Driver circuit between the A/C Heater Control C1 harness connector and the Mode Door 2 (Defrost to Floor) Actuator harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Go To 4

No

- Repair the (C801) Mode Door 2 Driver circuit for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

4. CHECK (C34) COMMON DOOR DRIVER CIRCUIT FOR AN OPEN




1. Measure the resistance of the (C34) Common Door Driver circuit between the A/C Heater Control C1 harness connector and the Mode Door 2 (Defrost to Floor) Actuator harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Replace the Mode Door 2 (Defrost to Floor) Actuator.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Repair the (C34) Common Door Driver circuit for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test.