Checking the connectors and wiring

Checking the power supply and ground terminals 

The following applies to components on the climate control unit that communicate with the climate control module (CCM) via LIN bus 1 and LIN bus 2:

• All components are jointly powered via a fuse from the central electronic module (CEM)
• All components are grounded via a common ground terminal.

Check the power supply to the components on the climate control unit by taking a reading on connector A for the central electronic module (CEM) between terminal #A44 (C44) and chassis ground.

Also check the fuse on the central electronic module (CEM).

Check the power supply cable between the central electronic module (CEM) and the connector for the climate control unit. Check for an open-circuit. Measure between terminal #1 on the connector for the climate control unit and chassis ground.

Check the ground terminal for the components on the climate control unit. Measure between the connector for climate control unit terminal #6 and chassis ground.

Check the connector for the climate control unit and connector A for the central electronic module (CEM). Check for contact resistance. Check for oxidation. Check for loose connections.

Checking LIN bus 

Check both LIN bus 1 and LIN bus 2. Check for an open-circuit.

Take readings between:

• The connector for climate control module (CCM) terminal #12 (#36) and the connector for climate control unit terminal #2
• The connector for climate control module (CCM) terminal #7 (#31) and the connector for climate control unit terminal #5.

Check the wiring between the connector and the components on the climate control unit. Check for an open-circuit.

Remedy as necessary.

Other information: 

• To connect the breakout box to the climate control module (CCM), see: Connecting the breakout box
• To connect the breakout box, central electronic module (CEM), see: Connecting the breakout box
• See Signal specification
• See Climate control, location of components
• See Dashboard environment panel (including climate control module (CCM)), replacing
• See Central electronic module (CEM), replacing
• See Checking wiring and terminals

Fig 3: Connector, Green (16- Pin)

Courtesy of VOLVO CARS OF NORTH AMERICA.

Refer to Verification