Air Conditioning Features

The expansion valve is now located in the evaporator housing for better noise suppression of its operation.

The evaporator is kept at a constant temperature of 35°-37°F when the compressor is running and is kept from freezing by cycling the compressor OFF. This is performed by the ECU from input of the evaporator temperature sensor.

The compressor is protected from overheating by a 302°F temperature switch located on its housing.

When pressing the air conditioner button the [1][2]auxiliary fan is turned on to its low speed. High speed of the fan is switched on if coolant temperature exceeds 210°F or if refrigerant pressure exceeds 17 bar (250 psi). A 10 second delay is provided so the high speed of the fan is not turned "on" when the compressor is disengaged.





More detailed information is available in the 1988 7-Series (E32) Electrical Troubleshooting Manual as shown:

Schematic drawings = 6450-00

Diagnostic procedures = 6450A-00

Circuit operation = 6450A-38