Checking contact resistance, oxidation

Remove relay and check relay socket contacts for contact resistance and oxidation as described in Contact resistance and oxidation .

Also check switch 54/20 or 54/21 (LH/RH) for contact resistance and oxidation as described in Contact resistance and oxidation .

Reassemble relay and switch.

Activate relay with switch unit on rear door, up/down.

If the function is now OK, this means that the fault was probably caused by a faulty contact in the relay socket.

Additional information: 

• To access the window lift relay, see Central electronic module (CEM), replacing .

Fig 1: Identifying Ohmmeter

Courtesy of VOLVO CARS OF NORTH AMERICA.

Fig 2: Identifying Relays

Courtesy of VOLVO CARS OF NORTH AMERICA.

Does it work? 

• YES 

  Refer to Verification 

• NO 

  Refer to Checking for open circuits from relay to motor