INFORMATION AND REPAIR
If the control module detects a fault
It stores a diagnostic trouble code (DTC) and the orange indicator LEDs in the REC and air conditioning (A/C) buttons flash for approximately 20 seconds.
Self-adjustment of blend door motors
The blend door motors are self-adjusting after any of them has been removed or replaced, or other work is carried out on the motor or linkage.
To activate self-adjustment, proceed as follows:
- Ignition ON, position I or II
- press in the REC button three times within three seconds.
NOTE! The control module automatically does a self-adjustment when it is connected to the car or when it registers that the power has been disconnected (e.g. battery disconnected) for more than 30 seconds.
How does the blend door motor function?
The motor sends a voltage signal back to the controller between 0.5V to 4.8V.
Based on the user's desired temperature, the motor turns to a desired position based on the voltage signal back from the motor.
If the motor turns more than the voltage limits, the calibration errors out and the motor is stuck in position until a calibration is successful.
Why does my blend door motor not calibrate?
I would say there are two main reasons the motor does not calibrate.
- The motor has an internal fault such as a failed component
- The black plastic shaft which the square drive slots into has cracked. When this square hole cracks, the shaft slips inside the square hole and prevents the motor from finding the two limit points.
How to fix the cracked black plastic input shaft
I bought "Brass Round Tube 300mm Length 11mm OD 0.5mm Wall Thickness" I cut this into a 3mm wide piece and hammered it on the end of the rod to clamp it shut.
This prevents the square drive of the motor slipping inside the hole and lets the motor calibrate.
