Heating and ventilation (Heater assembly): Description and operation

Heater assembly

1 Windscreen and side window air outlet 2 Face level air outlet 3 Casing 4 Rear footwell air outlet 5 Front footwell air outlet 6 Drain outlet 7 Air inlet

8 Engine coolant return 9 Engine coolant feed 10 Heater matrix 11 RH temperature control cable 12 Distribution control cable 13 LH temperature control cable

The heater assembly heats and distributes air as directed by selections made on the control panel. The assembly is installed on the vehicle centre-line, between the fascia and the engine bulkhead. The heater assembly consists of a casing, formed from a series of plastic moldings, which contains a heater matrix and control flaps. Internal passages integrated into the casing guide the air through the casing and separate it into two flows, one for the LH outlets and one for the RH outlets. Two drain outlets at the bottom of the casing connect to overboard drain tubes installed in the sides of the transmission tunnel.

Heater matrix The heater matrix provides the heat source to warm the air being supplied to the distribution outlets. The heater matrix is an aluminium two pass, fin and tube heat exchanger, installed in the RH side of the casing. Two aluminium tubes attached to the heater matrix extend through the engine bulkhead to connect the heater assembly to the engine coolant system. When the engine is running, coolant is constantly circulated through the heater matrix by the engine coolant pump. On diesel models, the coolant flow is assisted by an electric pump while the FBH system is active.