Solar Sensor
WARNING: This page is about a different car, the 1996 Saab 900 and 1995 Saab 900. However, it is still accessible from the selected car via links, so may be relevant.
The solar sensor is located on top of dashboard, and is used to measure infrared radiation (radiated heat). In the case of increased solar radiation and outside temperatures above 59°F (15°C), the A/C-heater control module increases the speed of the ventilation fan because a lower temperature has to be achieved.
Fan (blower motor) speed is changed immediately when solar sensor radiation changes. Due to the fact that the solar sensor measures infrared radiation, it cannot be tested with a fluorescent light. An incandescent light must be used for testing. If no solar sensor signal is obtained, a default value of zero volts (nighttime) is set.