Engine Coolant Temperature 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 engine coolant is connected to Integrated Central Electronics (ICE) system. The ICE system uses coolant temperature to control the radiator fan and to switch off A/C compressor at high temperatures. The ICE sends a square wave signal to the instrument cluster, which in turn, sends a coolant temperature signal to the A/C-heater control panel.

The A/C-heater control panel uses coolant temperature as an input value to decide whether the hot or cold starting mode of operation is applicable. If it is, air distribution and fan (blower motor) speed are adjusted as a function of the coolant temperature.

If no engine coolant temperature signal can be obtained, the A/C-heater control module calculates a default value of 32°F (0°C) upon starting which will gradually rise to 212°F (100°C).