Heater Control Module (J65) and Fresh/Recirculation Air Door Motor (V154), Checking

Heater Control Module (J65) and Fresh/Recirculation Air Door Motor (V154), Checking

Special tools, testers and auxiliary items required

• Voltage Tester (V.A.G 1527B)

- Remove the glove compartment.

- Switch ignition on.

- Turn rotary switch for air distribution - B - into "air distribution to instrument panel vents" position.






- Fresh/recirculating air button - F - is not operated (fresh air mode, button indicator lamp does not light up).

- Connect the (V.A.G 1527 B) - B - to check voltage at connector - A - between terminals 9 and 10 (to fresh/recirculating air door motor).






- Operate fresh/recirculating air button (button indicator lamp lights up).

- Ground (GND) is applied at terminal 9 continuously or only for a short time (depending on control module version) and Positive is applied at terminal 10 continuously or only for a short time.

- Fresh/Recirculating Air Door Motor and thus the fresh/recirculating air door moves into "recirculating air mode" position (recirculating air intake opening - C - is opened).

- Operate fresh/recirculating air button - F - (recirculating air, button indicator lamp goes out).






• By pressing fresh/recirculating air button - F -, heater control module changes the voltage supply to fresh/recirculation air door motor (B+ and GND are interchanged).

• Depending on the version of the heater control module, Positive is applied continuously or only for a certain period of time after pressing the fresh/recirculating air button. If this time has elapsed, the motor is only still actuated over a certain duty cycle for control modules on which the Positive is applied only for a certain period of time (lamp in (V.A.G 1527 B) only still blinks on briefly).

- Ground (GND) is applied at terminal 10 continuously or for a short time and Positive is applied at terminal 9 continuously or for a short time.






- Fresh/Recirculating Air Door Motor and thus the fresh/recirculating air door moves into "fresh air mode" position (recirculating air intake opening - C - is closed).

If no malfunction is detected during this test:

- Check fresh/recirculating air door for freedom of movement.

- Replace the fresh/recirculated air door motor. Refer to=> [ Fresh/Recirculation Air Door Motor (V154)/(V113) ] Fresh/Recirculation Air Door Motor (V154)/(V113).

Not OK?

- Check the wire connection between the heater control module and the fresh/recirculation air door motor for open circuit or short circuit.

- Check the voltage supply and the ground connection on the Heater control module (J65).

- Replace the heater control module. Refer to => [ Heater Controls ] Heater Controls.