Possible causes, elimination, notes

Diagnosis conditions 

No control module fault stored.

No fault with supply voltage (5 volts).

Outside temperature higher than - 40 °C.

Open circuit 

1. Unplug connector A from the heating/air-conditioning control.
2. Connect ohmmeter to connectors A 10 and A 12.

   Display: approx. 3 kohm at 23 °C

   NOTE: The wires to the interior temperature sensor are routed via two additional plug connections on the heating/air-conditioning control.
3. Unplug connector from the interior temperature sensor.
4. Connect ohmmeter to connector A 10 and interior sensor connector pin 5.

   Display: < 5 ohm

5. Connect ohmmeter to connector A 12 and interior sensor connector pin 4.

   Display: < 5 ohm

6. Connect voltmeter to connector A 10 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 ohm is displayed, check wiring harness for pinching and chafing damage.