Checking Pressure Switch (Pressostat)

WARNING: This page is about a different car, the 2002 Volvo C70, 2001 Volvo C70, 2000 Volvo C70, 1999 Volvo C70, and 1998 Volvo C70. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Engine Start Verification

Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 2: Disconnecting Connector

Courtesy of VOLVO CARS OF NORTH AMERICA.

Filling point low pressure side (blue hose) connected to service valve.
Engine idling.
Place blower fan switch to position 0.
Place air conditioning (A/C) switch to off.
Disconnect the pressure switch (Pressostat) connector.
Start the compressor by connecting the magnetic clutch cable to the battery positive terminal.

WARNING: The compressor may be connected like this for a maximum of 3 minutes.

Connect an ohmmeter over both pressure switch (Pressostat) terminals.

NOTE: If the pressure falls below 140 kPa (20.3 psi), but the ohmmeter continues to display 0 Ω , stop and disconnect the compressor.

Fig 3: Identifying Canister Purge Valve Terminals
Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 4: Identifying Ohmmeter
Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 5: Identifying Blower Fan Switch And Air Conditioning (A/C) Switch
Courtesy of VOLVO CARS OF NORTH AMERICA.

The ohmmeter should read infinite resistance at a compressor pressure of 150-170 kPa (21.8 - 24.7 psi).

OK
Refer to Fault-Tracing Information
NOT OK
Refer to Replacing Component