A/C Pressure Switch, Checking

A/C Pressure Switch, Checking

Visual check: Ensure that O-ring (color: red) 10.8 mm x 1.8 mm is seated in groove.

Switch function between contacts -T4a/1- and -T4a/2- (at connector housing) switches A/C Clutch N25 off whenever:
- excessive refrigerant circuit pressure is present (e.g.: insufficient air flow over condenser or if system is overcharged)
- insufficient refrigerant circuit pressure is present (e.g.: when refrigerant has leaked out).

Switch function between contacts -T4a/3- and -T4a/4- (at connector housing) switches Coolant Fan V7 to 2nd speed when refrigerant pressure rises.







Switching conditions
- Contacts - 1 - and - 2 - open below 1.2 bar (17.4 psi) and closed above 2.4 bar (34.8 psi) switching threshold
- Contacts - 1 - and - 2 - open above 32 bar (464 psi) and closed below 24 bar (348 psi) switching threshold
- Contacts - 3 - and - 4 - closed above 16 bar (232 psi) and open below 12.5 bar (181.2 psi) switching threshold







Switch function, checking
- Bridge contacts - 1 - and - 2 - with engine running. If A/C Clutch N25 switches on, refrigerant system may be empty. A/C Refrigerant System, Testing With Pressure Gauges