The Saab NG900 - Technical - Interior

Heater/Blower fan does not work

Diagnostic procedure

1. Check fuse 3 and that it is live.

2. Unplug the 8-pin connector from the rear of the control panel and check whether pin 2 of the connector is live.

3. Check the wiring between pin 2 of the control panel and fuse 3 for continuity/shorting.

4. Unplug the fan's connector and check the voltage as shown below:

• Fan speed 1 should give a reading of 12 V on pin 1 (RD/WH)

• Fan speed 2 should give a reading of 12 V on pin 2 (WH)

• Fan speed 3 should give a reading of 12 V on pin 4 (GN)

• Fan speed 4 should give a reading of 12 V on pin 3 (YE)

Also check whether the resistance across pin 5 and a good grounding point is < 0.1 ohm.

Try fitting a new fan resistor if all readings are correct.

5. Check the voltage on the following pins at the rear of the control panel's 8-pin connector. Readings should be taken with the fan connector unplugged and the control panel connector plugged in.

• Fan speed 1 should give a reading of 12 V on pin 1

• Fan speed 2 should give a reading of 12 V on pin 7

• Fan speed 3 should give a reading of 12 V on pin 6

• Fan speed 4 should give a reading of 12 V on pin 3 Change the control panel if any reading is incorrect.

6. Check the leads for shorting/continuity if correct readings were obtained when carrying out point 5 but not when carrying out point 4.

Please note: This is an enthusiast's web site and is not in any way affiliated with Saab Automobile. All information is presented in good faith. However, I am not a trained mechanic, just an enthusiast. It is your responsibility to ensure that you are competent to carry out any procedures presented here and that they are correct. No responsibility can be accepted for any inaccuracies or consequential loss, injury or damage. Copyright © 2004 - 2005 Munki
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