Checking The Wiring And Terminals

Fig 1: Identifying Ignition In Off Position

Courtesy of VOLVO CARS CORPORATION

Fig 2: Identifying Microphone Connectors

Courtesy of VOLVO CARS CORPORATION

Disconnect any connection from the socket for the tow hitch connector.
Ignition off.
Cut off voltage feed to Trailer module (TRM) by removing the battery's minus cable.
Disconnect the connector for the Trailer module (TRM).
Disconnect the connector from the vehicle's left tail light.
Check connectors for damage to pins and connections.

Check the connectors. Check for loose connections. Check for contact resistance. Check for oxidation.

Check the lead for open circuit or short-circuiting to ground.

Take readings between:
- Trailer module (TRM) #C2: 3(#24) and the connector for the vehicle's left tail light #C1: 6.
- The vehicle's left tail light #C1: 6 and central electronic module (CEM) C2: 59.
Remedy as necessary.

Other information
- Trailer module (TRM): CONNECTING THE BREAKOUT BOX
- Central electronic module (CEM): CONNECTING THE BREAKOUT BOX
- Trailer module (TRM): SIGNAL SPECIFICATION
- Central electronic module (CEM): SIGNAL SPECIFICATION
- see BATTERY DISCONNECTING AND CONNECTING
- see TRAILER MODULE (TRM)
- Central electronic module (CEM): CONTROL MODULE RELAY BOX PASSENGER COMPARTMENT
- see CHECKING WIRING AND TERMINALS