Air Conditioning Compressor Control System

Air Conditioning Compressor Control System

The DME system activates the compressor via a relay at the earliest approx. 8 seconds after starting the engine. This relay is located in relay carrier 2.

The following conditions result in "Shut-down of the a/c compressor":
- Temperature conditions
- At outside temperatures of < 37.4 °F. (3 °C) (see also section on "Temperature sensor for fresh air intake") the compressor is shut down. The control unit only allows the compressor to be switched on again at 38 °F. (3.5 °C).
- The compressor is shut down at coolant temperatures of > 244 °F. (118 °C) and restarted at < 239 °F. (115 °C).

- Pressure conditions
The compressor is switched off at coolant pressures of less than 29 psi (2 bar) (low pressure) and greater than 406 psi (28 bar) (high pressure).

- Kickdown conditions (acceleration)
At a pedal travel of > 92 % (shortly before pedal stop), the compressor is - when the pedal travel deviation is less than 6 seconds - switched off for 6 seconds or for a maximum of 9 seconds (duration of pedal travel deviation greater than 6 seconds). Classic full load cut-off is not incorporated.