Floor/Defrost Mode Door Control Circuit Low (Dual-Zone)
B1047-FLOOR/DEFROST MODE DOOR CONTROL CIRCUIT LOW (DUAL-ZONE)
For a complete wiring diagram refer to Diagrams/Electrical.
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 DTCs can set at the same time for multiple actuators depending upon the type of short, its location, and the direction the actuator is moving when the short is present.
- When Monitored:
When the Actuator DTC Detection Test is executed.
- Set Condition:
If the (C801) Mode Door 2 Driver circuit is shorted to ground.
Diagnostic Test
1. CHECK (C801) MODE DOOR 2 DRIVER CIRCUIT FOR A SHORT TO GROUND
NOTE: If present, diagnose and repair DTC B10AB Right Blend Door Control Circuit High or B10AA Right Blend Door Control Circuit Low before proceeding.
Turn the ignition off.
Disconnect the A/C Heater Control C1 harness connector.
Measure the resistance of the (C801) Mode Door 2 Driver circuit between ground and the A/C Heater Control C1 harness connector.
Is the resistance below 10k ohms?
Yes
- Repair the (C801) Mode Door 2 Driver circuit for a short to ground.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
No
- Go To 2
2. CHECK (C801) MODE DOOR 2 DRIVER CIRCUIT FOR A SHORT TO OTHER DOOR DRIVER CIRCUITS
Measure the resistance between the (C801) Mode Door 2 Driver circuit and the (C61) Blend Door Driver circuit, the (C32) Recirculation Door Driver circuit, the (C29) Mode Door 1 Driver circuit, and the (C33) Passenger Blend Door Driver circuit in the A/C Heater Control C1 harness connector.
Is the resistance below 10k ohms between the (C801) Mode Door 2 Driver circuit and any of the other door driver circuits?
Yes
- Repair the circuit(s) with a resistance below 10k ohms for a short to the (C801) Mode Door 2 Driver circuit.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
No
- Go To 3
3. CHECK MODE DOOR 2 (DEFROST TO FLOOR) ACTUATOR CIRCUIT RESISTANCE
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 below 30 ohms?
Yes
- Go To 4
No
- Go To 5
4. CHECK (C801) MODE DOOR 2 DRIVER CIRCUIT FOR A SHORT TO (C34) FRONT COMMON DOOR DRIVER CIRCUIT
Disconnect the Mode Door 2 (Defrost to Floor) Actuator harness connector.
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 below 10k ohms?
Yes
- Repair the (C801) Mode Door 2 Driver circuit for a short to the (C34) Common Door Driver circuit.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
No
- Replace the Mode Door 2 (Defrost to Floor) Actuator.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
5. RUN THE ACTUATOR DTC DETECTION TEST
Reconnect the A/C Heater Control C1 harness connector.
Turn the ignition on.
With the scan tool, erase HVAC DTCs.
With the scan tool, select System Tests and then select Actuator DTC Detection. When the test is complete, select View DTCs.
Does the scan tool only display: B1047-FLOOR/DEFROST MODE DOOR CONTROL CIRCUIT LOW?
Yes
- Replace the A/C Heater Control.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
No, Other DTC(s) Displayed
- Diagnose and repair the DTC(s). If multiple DTCs are present, beginning with the passenger blend door, diagnose and repair all short high DTCs and then all short low DTCs.
No, And No Other DTCs Displayed
- Using the wiring diagram as a guide, inspect the wiring and connectors for conditions causing an intermittent short. Repair as necessary.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test