The subsequent data applies to non-air-conditioned models as well as to those having a manually operated air conditioning system; where an automatic air conditioning system is present, the dismantling and re-fitting of the heater/ventilation system parts should be done by an Audi/VAG dealer as a special electrical equipment is required to re-set the system. The control unit is easy to remove by removing the negative lead of the battery, removing the centre console, unscrewing the retaining screws releasing the control panel off the facia, disconnecting the wiring connectors, detaching the cables with noting the positions they have been installed, and lastly extracting the control panel of the vehicle. Refitting is the process that entails the reversal of the steps used to remove the control cables without forgetting to make sure that the control cables are well reconnected and that the controls are working as they should. To do it on right hand and left hand drive models with air conditioning, remove heater/ventilation housing assembly then air intake duct/flap and then the motor may be removed by removing circlip which holds the motor in place and then checking the seal. To get the motor bearings lubricated, the circlip fitted in the right place and the air intake firmly fitted. In models with no air conditioning (left-hand drive models), it involves the removal of a water deflector panel, battery, pollen filter and air intake flap assembly then the disconnection of the blower motor and removal as well. The resistor on the blower motor can be withdrawn by detaching the wiring connector and detaching the retaining screws and vice versa. The heater/ventilation housing can be taken out in a couple of phases, which include the windscreen wipers motor and battery and heater control and glovebox, storage compartment panel, and a variety of ducts are removed, and finally the heater/ventilation housing is lifted out. To refit it it is important that all the parts are properly attached and the coolant hoses are properly reattached. The heater matrix removal itself consists of the halves of the housing being separated, the sealing foam of the matrix being inspected, and correct alignment in assembling the housing halves, the silicone adhesive sealant being required to seal the joint. To remove auxiliary heater with A6 diesel engine models, the housing should be dismantled to release auxiliary heater and then it should be reassembled to the housing.