1 - High pressure switch
2 - Refrigeration lines
3 - Low pressure switch
4 - Electrical connector
Since working on the system is potentially dangerous, we strongly recommend that all work related to the air conditioning system be carried out by a BMW dealer or air conditioning specialist. At least don't remove any system components (hoses, compressor, fittings, etc.) until the system is completely discharged by a qualified technician. Read the precautions at the beginning of the Section Air Conditioner Maintenance and Precautions.
Withdrawal
1. Discharge the air conditioning system (see warning above).
2. Disconnect the negative battery cable.
If your car's radio is equipped with an anti-theft system, make sure you have entered the correct code before disconnecting the battery.
If, after connecting the battery, the inscriptions on the instrument panel appear in the wrong language, refer to Section Anti-theft audio system and instrument panel language, for instructions on how to set the desired language.
3. Remove the windshield washer reservoir.
4. Disconnect the electrical connector (connectors) battery/dehydrator - note that not all models have both high and low pressure switches.
5. Disconnect the refrigerant lines from the accumulator/dehydrator.
6. Seal open fittings to prevent dirt and moisture from entering.
7. Give fixing screws and remove the accumulator/dehydrator.
Installation
If you are installing a new battery/dehydrator it may be necessary to add some refrigerant oil - in this case follow the manufacturer's instructions.
1. Remove old o-rings from refrigeration lines and install new ones. This should be done regardless of which battery/dehydrator is installed.
2. If you are installing a new accumulator/dehydrator, remove the pressure switches from the old unit and put them on the new unit before installing it. Not all models are equipped with both low and high pressure switches.
3. Lubricate O-rings with refrigerant oil prior to installation.
4. Install in reverse order, but remember to lubricate the O-rings with refrigerant oil before connecting the fittings.
5. Have the system drained, charged, and leak tested by the same qualified person who discharged it.