Volkswagen Passat 1995 Official Factory Repair Manual page 4170

A/C refrigerant system, servicing
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Fig. 3 A/C pressure switch -F129-, checking
The pressure switch can be removed without
discharging refrigerant system.
Visually check that O-ring 10,8 mm x 1,8 mm is
positioned correctly in the groove.
Function
Switch part between terminals 1 and 2 switches off
the A/C clutch -N25- when the system pressure is too
high or when there is not enough refrigerant in the
system .
Switch opens when the pressure is below 1.2 bar
and closes again above 2.4 bar (switch point).
Switch opens above 32 bar and closes again
below 24 bar (switch point).
Switch part between terminals 3 and 4 switches
coolant fan -V7- (via the coolant fan control module -
J293-) to the next higher fan speed when system
pressures increase.
Switch closes above 16 bar and opens again
below 12.5 bar (switch point).
Checking, continued
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12/7/2004