B104D

B104D-BLEND DOOR CONTROL CIRCUIT LOW (SINGLE-ZONE)





For a complete wiring diagram,refer to the Wiring Information Electrical Diagrams.

Theory of Operation

The A/C Heater Control drives the Blend Door Actuator via the (C61) Blend Door 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 (C61) Blend Door Driver circuit is shorted to ground.





1. CHECK (C61) BLEND DOOR DRIVER CIRCUIT FOR A SHORT TO GROUND




1. Turn the ignition off.
2. Disconnect the A/C Heater Control C1 harness connector.
3. Measure the resistance of the (C61) Blend Door Driver circuit between ground and the A/C Heater Control C1 harness connector.

Is the resistance below 10k Ohms?

Yes

- Repair the (C61) Blend Door Driver circuit for a short to ground.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 2

2. CHECK (C61) BLEND DOOR DRIVER CIRCUIT FOR A SHORT TO OTHER DOOR DRIVER CIRCUITS




1. Measure the resistance between the (C61) Blend Door Driver circuit and the (C29) Mode Door 1 Driver circuit, the (C32) Recirculation Door Driver circuit, and the (C801) Mode Door 2 Driver circuit in the A/C Heater Control C1 harness connector.

Is the resistance below 10k Ohms between the (C61) Blend Door 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 (C61) Blend Door Driver circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 3

3. CHECK BLEND DOOR ACTUATOR CIRCUIT RESISTANCE




1. Measure the resistance between the (C61) Blend Door 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 (C61) BLEND DOOR DRIVER CIRCUIT FOR A SHORT TO (C34) COMMON DOOR DRIVER CIRCUIT




1. Disconnect the Blend Door Actuator harness connector.
2. Measure the resistance between the (C61) Blend Door 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 (C61) Blend Door Driver circuit for a short to the (C34) Common Door Driver circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Replace the Blend Door Actuator.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

5. RUN THE ACTUATOR DTC DETECTION TEST
1. Reconnect the A/C Heater Control C1 harness connector.
2. Turn the ignition on.
3. With the scan tool, erase HVAC DTCs.
4. 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: B104D-BLEND DOOR CONTROL CIRCUIT LOW?

Yes

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

No, Other DTC(s) Displayed

- Diagnose and repair the other DTC(s). If multiple DTCs are present, beginning with the common circuit, 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 the BODY VERIFICATION TEST. Body Verification Test.