Control Module HVAC: Service Precautions

General Repair Information

• A data plate in engine compartment indicates the refrigerant used and capacity.

All vehicles


Before working on electrical system (wiring), remove relevant fuse(s).

• Disconnect the battery (A) , the auxiliary battery (A1) and the traction battery (A2) before starting any electric welding on the vehicle.

The A/C refrigerant system may be drained and opened only if it is for safety reasons, refer to => [ A/C and Refrigerant Safety Precautions ] A/C and Refrigerant Safety Precautions or if components of the A/C refrigerant system must be replaced, refer to => [ Refrigerant Circuit Draining ] Refrigerant Circuit Draining.

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

Repairs to the heating and A/C without opening the refrigerant circuit are possible and are described in => [ Refrigerant Circuit Component Overview ] Refrigerant Circuit Component Overview or => [ Refrigerant Circuit Component Overview ] Refrigerant Circuit Component Overview, => [ A/C System Control and Regulation Components Outside Passenger Compartment ] A/C System Control and Regulation Components Outside Passenger Compartment and => [ 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 in any Audi and Volkswagen workshop even though the refrigerant circuit is fully charged.

Service work on the A/C system that requires the refrigerant circuit to be discharged and thus cannot be performed in every Audi and Volkswagen workshop are described in=> [ 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.

• Contact corrosion, refer to => [ Contact Corrosion ] Contact Corrosion.

• A/C components controlled or activated by other control modules, electrical tests, refer to => [ A/C Components Controlled or Activated by Other Control Modules, Electrical Tests ] Testing and Inspection.

• Components actuated by A/C system, electrical test, refer to => [ Components Actuated by A/C System, Electrical Test ] Components Actuated by A/C System, Electrical Test.