9000 Hatchback L4-2290cc 2.3L DOHC Turbo EFI (1994)
High Pressure Sensor / Switch: Description and Operation
Year model M1985:
The pressure switch disconnects the compressor if system pressure drops below 2.7 kPa (38 psi).
The compressor is then switched on again when pressure has risen to 3.1 kPa (44 psi). This protects the compressor from working at too low pressure
(running dry).
If outside temperature drops below about + 5° C (41° F), the pressure is the system becomes so low (below 2.8 kPa, 39.4 psi), that the compressor is
switched on.
Year model M1986-
The function of the pressure switch is extended and it becomes a three stage switch with the following functions:
Stage 1:
Allows the compressor to work at temperatures down to ± 0° C (32° F). Pressure in the system at this temperature is about 2 bar (29 psi).
Stage 2:
Starts the engine's electric radiator fan at a pressure of about 15 bar (21O psi). When pressure has dropped to about 11 bar (155 psi),the fan is again
disconnected. For R134a refrigerant, the fan is started at. 16.5 bar (239 psi) and disconnected at about 12.5 bar (181 psi).
Stage 3:
This is a safety feature which breaks the electrical circuit to the compressor if pressure exceeds 27 bar (380 psi) for R12 refrigerant. When pressure has
then dropped below 6 bar (9O psi), the compressor is reconnected. For R134a refrigerant the switch breaks at 3O bar (435 psi).
