Vacuum System, HVAC

Vacuum System





- The vacuum supply to the five solenoids in the system is from the engine inlet manifold via a reservoir and non-return valve. The vacuum solenoids are located beneath the heater assembly.

- Components operated by the solenoids are:
1 The defrost/Demist flaps which are held closed by vacuum, are fed by a GREEN vacuum supply tube.
2 The recirculation/fresh air flaps which are held closed by vacuum, are fed by a BLUE vacuum supply tube.
3 The center vent, which is opened by vacuum, is fed by a BLACK vacuum supply tube.
4 The coolant valve, which is closed by vacuum, is fed by a RED vacuum supply tube.
5 The manual recirculation flap is fed by a WHITE vacuum supply tube.

NOTE:
- Items 1 to 4 are integrated. Item 5 has no connection to the heater control module (HCM).
- The vacuum supply to item 1 is restricted to reduce operating noise.
- Items 2 & 3 are restricted to damp the system and to avoid hunting. (Recirculation and center vent flaps can take up to 30 seconds to change state). Items 4 & 5 are unrestricted.