B1059

B1059-RECIRCULATION DOOR CONTROL CIRCUIT LOW (MTC)

B1059 - Recirculation Door Control Circuit Low (MTC):

Theory of Operation
The A/C Heater Control drives the Recirculation Door Actuator via the (C32) Recirculation Door Driver circuit and the (C34) Front Common Door Driver circuit. All of the front door actuators share the (C34) Front 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 (C32) Recirculation Door Driver circuit is shorted to ground.

POSSIBLE CAUSES
- (C32) Recirculation door driver circuit shorted to ground
- (C32) Recirculation door driver circuit shorted to other door driver circuit(s)
- Recirculation door actuator
- A/C heater control

Diagnostic Test

1. CHECK (C32) RECIRCULATION DOOR DRIVER CIRCUIT FOR A SHORT TO GROUND




Turn the ignition off.
Disconnect the A/C Heater Control C1 harness connector.
Measure the resistance of the (C32) Recirculation Door Driver circuit between ground and the A/C Heater Control C1 harness connector.

Q: Is the resistance below 10k ohms?

YES: Repair the (C32) Recirculation Door Driver circuit for a short to ground.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 2

2. CHECK (C32) RECIRCULATION DOOR DRIVER CIRCUIT FOR A SHORT TO OTHER DOOR DRIVER CIRCUITS




Measure the resistance between the (C32) Recirculation Door Driver circuit and the (C29) Mode Door 1 Driver circuit, the (C61) Front Blend Door Driver circuit, the (C801) Mode Door 2 Driver circuit, and, if equipped, the (C53) Rear Mode Door Driver circuit, the (C154) Rear Common Door Driver circuit, and the (C54) Rear Blend Door Driver circuit in the A/C Heater Control C1 harness connector.

Q: Is the resistance below 100 ohms between the (C32) Recirculation Door Driver circuit and any of the other door driver circuits?

YES: Repair the circuit(s) with a resistance below 100 ohms for a short to the (C32) Recirculation Door Driver circuit.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 3

3. CHECK RECIRCULATION DOOR ACTUATOR CIRCUIT RESISTANCE




Measure the resistance between the (C32) Recirculation Door Driver circuit and the (C34) Front Common Door Driver circuit in the A/C Heater Control C1 harness connector.

Q: Is the resistance below 30 ohms?

YES: Go To 4
NO: Go To 5

4. CHECK (C32) RECIRCULATION DOOR DRIVER CIRCUIT FOR A SHORT TO (C34) FRONT COMMON DOOR DRIVER CIRCUIT




Disconnect the Recirculation Door Actuator harness connector.
Measure the resistance between the (C32) Recirculation Door Driver circuit and the (C34) Front Common Door Driver circuit in the A/C Heater Control C1 harness connector.

Q: Is the resistance below 100 ohms?

YES: Repair the (C32) Recirculation Door Driver circuit for a short to the (C34) Front Common Door Driver circuit.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Replace the Recirculation Door 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.
Turn the ignition off, wait 10 seconds, and then turn the ignition on.
With the scan tool, select System Tests and then select Actuator DTC Detection. When the test is complete, select View DTCs.

Q: Does the scan tool only display: B1059-RECIRCULATION 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 other DTC(s). If multiple DTCs are present, beginning with the common circuits, diagnose and repair all short high DTCs and then all short low DTCs. Refer to the Trouble Code Diagnostic Charts for a complete list of all HVAC related symptoms.

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