Control Module HVAC: Service Precautions

General Repair Information

Vehicles with Start/Stop System

On vehicles with the Start/Stop System, the engine could start automatically causing serious personal injury.

• If the Start/Stop System is activated (recognizable by a message in the instrument cluster), it is possible to start the engine automatically.

• Make sure the Start/Stop System is deactivated is deactivated (ignition switched off) whenever working on the vehicle.

All vehicles

Before working on the electrical wires, remove the relevant fuse(s).

• Disconnect the battery before performing any electric welding on the vehicle.

The refrigerant circuit of the A/C system may be discharged and opened, refer to=> [ Refrigerant Circuit, Draining ] Refrigerant Circuit, Draining only if this is necessary because of safety precautions, refer to (=> [ A/C and Refrigerant Safety Precautions ] A/C and Refrigerant Safety Precautions) or if components of the refrigerant circuit of the A/C system have to be to replaced.

When performing all other usual vehicle repair work, the refrigerant circuit of the A/C system should remain closed.

Servicing operations that can be performed on the heating and air conditioning system without opening the refrigerant circuit are described in this repair manual.

• Refrigerant circuit repair work, refer to=> [ Refrigerant Circuit Components Overview ] Refrigerant Circuit Components Overview.

• A/C system control and regulation components outside the passenger compartment, refer to=> [ A/C System Control and Regulation Components Outside Passenger Compartment ] A/C System Control and Regulation Components Outside Passenger Compartment.

• A/C system control and regulation components inside the passenger compartment, refer to=> [ A/C System Control and Regulation Components Inside Passenger Compartment ] A/C System Control and Regulation Components Inside Passenger Compartment.

• The connections for the senders/switches described in this Workshop Manual are fitted with a valve which closes automatically when the switches are unscrewed. These switches can thus be replaced at any workshop even with a fully charged refrigerant circuit.

Repair work on the A/C system that requires the refrigerant circuit to be discharged and thus cannot be performed at any workshop is described from => [ Refrigerant Circuit, Servicing ] Refrigerant Circuit, Servicing. Certain tools are required to discharge the refrigerant circuit, these work procedures must only be performed by trained personnel as well. Therefore, bring vehicle to a workshop that has the necessary tools and in which the work can be performed accordingly by qualified personnel if necessary.

• A/C components controlled or activated by other control modules refer to=> [ A/C Components Controlled or Activated by Other Control Modules ] A/C Components Controlled or Activated By Other Control Modules.

• Components actuated by a/c system, refer to => [ Components Actuated by A/C System ] Components Actuated By A/C System.