SAAB WIS ONLINE

AMBIENT SENSOR

AMBIENT SENSOR

TROUBLE SYMPTOM:

Fan speed is not switched when the fan speed control dial is in AUTO position.

WIRING DIAGRAM:


CHECK AMBIENT SENSOR.

Turn the ignition switch to OFF.

Disconnect the connector from ambient sensor.

Measure the resistance between connector terminals of ambient sensor.

Terminals

No. 1 — No. 2:

Is the resistance approx. 2.2 kΩ at 25°C (77°F)?

Yes


No

Replace the ambient sensor.


CHECK INPUT SIGNALS FOR AMBIENT SENSOR.

Turn the ignition ON.

Measure the voltage between (F78) connector terminals.

Connector & terminal

(F78) No. 1 (+) — No. 2 (−):

Is the voltage approx. 5 V?

Yes


No


CHECK OUTPUT SIGNALS FROM AUTO A/C CONTROL MODULE.

Turn the ignition switch to OFF.

Pull out the auto A/C control unit.

Disconnect the connector from ambient sensor.

Turn the ignition switch to ON.

Measure the voltage between connector terminals of auto A/C control module.

Connector & terminal

(B283) No. 9 (+) — No. 17 (−):

Is the voltage approx. 5 V?

Yes


No


CHECK HARNESS CONNECTOR BETWEEN AUTO A/C CONTROL MODULE AND AMBIENT SENSOR.

Turn the ignition switch to OFF.

Disconnect the connectors from auto A/C control module.

Measure the resistance of harness between auto A/C control module and ambient sensor.

Connector & terminal

(F78) No. 1 — (B283) No. 9:

Is the resistance less than 1 Ω?

Yes


No

Repair the open circuit in harness between auto A/C control module and ambient sensor.


CHECK HARNESS CONNECTOR BETWEEN AUTO A/C CONTROL MODULE AND AMBIENT SENSOR.

Measure the resistance of harness between auto A/C control module and ambient sensor.

Connector & terminal

(F78) No. 2 — (B283) No. 17:

Is the resistance less than 1 Ω?

Yes


No

Repair the open circuit in harness between auto A/C control module and ambient sensor.


CHECK POOR CONTACT IN AUTO A/C CONTROL MODULE CONNECTOR.

Check poor contact in auto A/C control module connector.

Is there poor contact in connector?

Yes

Repair the connector.


No

Replace the auto A/C control module.