B1040

B1040-PANEL MODE DOOR 1 CONTROL CIRCUIT/PERFORMANCE







Theory of Operation

After the initial installation of the A/C Heater Control, the controller is calibrated to each individual blend/mode door actuator. These calibrations are stored as in the number of pulses it takes to move the door from one stop to another. The A/C Heater Control drives the Door Actuators by the use of Door Driver circuit and a Common Door Driver circuit and monitors all door actuator pulses to detect door movement in both directions. Most of the door actuators share a common door driver circuit but each door actuator has its own unique driver circuit. Due to shared circuitry, similar DTCs can set at the same time for multiple actuators depending upon the type of circuit malfunction, its location, and the direction the actuator is moving when the malfunction is present.

- When Monitored:
With the ignition on and an actuator movement is commanded by the A/C Heater Control or during an HVAC Actuator Calibration Test.

- Set Condition:
If an actuator move is commanded by A/C Heater Control and an overcurrent condition is detected in either clockwise or counterclockwise movement for the period of five seconds. If the A/C Heater Control detects valid current draw for ten seconds, the DTC will change from Active to Stored and will stay in the controllers memory for 100 ignition cycles.





Always perform the HVAC Pre-Diagnostic Troubleshooting procedure before proceeding. HVAC Pre-Diagnostic Troubleshooting Procedure.

1. CHECK IF DTC IS ACTIVE
1. Ignition on, engine not running.
2. With the scan tool, read HVAC DTCs.

Is this DTC active?

Yes

- Go To 3

No

- Go To 2

2. PERFORM HVAC ACTUATOR CALIBRATION TEST
1. With the scan tool, perform the HVAC Actuator Calibration Test.

Did this DTC change from Stored to Active while performing the HVAC Actuator Calibration Test?

Yes

- Go To 3

No

- Go To 9

3. CHECK THE (C35) MODE DOOR DRIVER CIRCUIT FOR A SHORT TO VOLTAGE




1. Turn the ignition off to the lock position.
2. Disconnect the A/C Heater Control C1 harness connector.
3. Disconnect the Mode Door Actuator harness connector.
4. Ignition on, engine not running.
5. Measure the voltage of the (C35) Mode Door Driver circuit.

Is there any voltage present?

Yes

- Repair the (C35) Mode Door Driver circuit for a short to voltage.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Go To 4

4. CHECK THE (C34) COMMON DOOR DRIVER CIRCUIT FOR A SHORT TO VOLTAGE




1. Measure the voltage of the (C34) Common Door Driver circuit.

Is there any voltage present?

Yes

- Repair the (C34) Common Door Driver circuit for a short to voltage.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Go To 5

5. CHECK THE (C35) MODE DOOR DRIVER CIRCUIT FOR A SHORT TO GROUND




1. Turn the ignition off to the lock position.
2. Measure the resistance between ground and the (C35) Mode Door Driver circuit.

Is the resistance below 100k Ohms?

Yes

- Repair the (C35) Mode Door Driver circuit for a short to ground.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Go To 6

6. CHECK THE (C34) COMMON DOOR DRIVER CIRCUIT FOR A SHORT TO GROUND




1. Measure the resistance between ground and the (C34) Common Door Driver circuit.

Is the resistance below 100k Ohms?

Yes

- Repair the (C34) Common Door Driver circuit for a short to ground.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Go To 7

7. CHECK THE MODE DOOR
1. Remove the Mode Door Actuator and check the Mode Door for binding and full travel.

Were there any problems found?

Yes

- Repair or replace the Mode Door as necessary.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Go To 8

8. CHECK THE MODE DOOR ACTUATOR
1. Replace the Mode Door Actuator.
2. With the scan tool, erase HVAC DTCs and perform the HVAC System Test.

Did this DTC reset?

Yes

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

No

- Test complete.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

9. CHECK THE WIRING AND CONNECTORS
1. The conditions necessary to set the DTC are not present at this time.
2. Using the scan tool, check the Environmental Data to help identify the conditions in which the DTC was set.
3. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
4. Wiggle the wiring and connectors while checking for shorted and open circuits.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Test complete.