B1040-Panel Mode Door 1 Control Circuit/Performance: Notes

For a complete wiring diagram, refer to appropriate SYSTEM WIRING DIAGRAMS information.

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 Diagnostic Trouble Codes (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 10 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. Refer to HVAC .