Possible causes, elimination, notes

Diagnosis conditions 

No control module fault stored.

No fault with supply voltage (5 volts).

Open circuit 

1. Unplug connector A from the heating/air-conditioning control.
2. Connect ohmmeter to connectors A 7 and A 12.

   Display: approx. 1.2 kohm at 23 °C

3. Unplug connector from the outside temperature sensor.
4. Connect ohmmeter to connector A 7 and pin 1 (connector of outside temperature sensor).

   Display: 0 - 5 ohm

5. Connect ohmmeter to connector A 12 and pin 2 (connector of outside temperature sensor).

   Display: 0 - 5 ohm

6. Connect voltmeter to connector A 7 and ground. Switch on ignition.

   Display: 0 volts

   If approx. 5 volts are displayed, check wiring harness for pinching and chafing damage.

Short to ground 

1. Unplug connector A from the heating/air-conditioning control.
2. Connect ohmmeter to connector A 7 and ground.

   Display: "INFINITY" ohm

   If 0 - 5 ohmis displayed, check wiring harness for pinching and chafing damage.