9000 CSE V6-2962cc 3.0L DOHC (B308) (1996)
controlled by the rheostat that feeds pin 32 on the control module with a PWM signal (pulse width modulated) in the range 13 - 100% depending on the
position of the rheostat. The light must be switched on. With the light switched off, there is no rheostat voltage to the EDU, which then assumes the
"rheostat value" to be 100%.
When driving in daylight, the light in the cabin is measured by a light sensor on the Saab Car Computor (SCC) unit or on the front of the clock.
Depending on the intensity of the light, pin 36 on the control module is fed by the light sensor that controls the lighting with a voltage in the range 0 V -
10 V.
Speed Signal
The vehicle speed sensor in the gearbox sends a sin wave alternating voltage to the speedometer. The frequency of the voltage is proportional to the
speed of the sensor spindle (16 Hz/sensor revolution) and the amplitude increases with the frequency.