XJ-6 L6-4.2L (1983)
The camshaft moves to the full heat position closing the upper and lower cooling flaps and opening the heater flaps. However, the lower
heating flap which normally is held open by a vacuum actuator, does not have a vacuum feed, therefore, is held closed by the return spring.
All heated air is directed to the screen outlets. Manual operation of the dash end outlets is optional for side window defogging.
The vacuum switch on the manual control is closed preventing vacuum to the lower heating flap and screen outlet flaps (which allow screen
flaps to open 90% of air flow). There is a small bleed (10%) of hot air to the footwells. The fans are naturally on HIGH speed (4th) and will
come on immediately.
The heating system will not function until the engine water temperature reaches 40°C (103°F).
