Pinpoint Test Z: The Trailer Lamps Are Inoperative - Trailer Parking Lamps

WARNING: This page is about a different car, the 2006 Ford F550 Super Duty, 2006 Ford F450 Super Duty, and 2006 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

Z1 CHECK CIRCUIT 962 (BN/WH) FOR VOLTAGE
- Disconnect: Trailer Tow C4098 (4-Pin).
- Disconnect: Trailer Tow C4099 (7-Pin).
- Place the headlamp switch in the parking lamps ON position.
- Measure the voltage between the trailer tow C4098-3, circuit 962 (BN/WH) (4-pin connector), harness side and ground; or between the trailer tow C4099-6, circuit 962 (BN/WH) (7-pin connector), harness side and ground.
  
  Fig 1: Checking Circuit 962 (BN/WH) For Voltage
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
Yes : The vehicle is operating correctly. SEND the trailer to an authorized camper/trailer repair facility.

No : GO to Z2.
Z2 CHECK CIRCUIT 962 (BN/WH) FOR AN OPEN
- Place the headlamp switch in the OFF position.
- Disconnect: CJB C270j.
- Place the headlamp switch in the parking lamps ON position.
- Measure the voltage between the CJB C270J pin 15, component side and ground.
  
  Fig 2: Checking Circuit 962 (BN/WH) For Open
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
Yes : REPAIR the circuit. TEST the system for normal operation.

No : VERIFY the CJB fuse 38 (20A) is OK. If OK, INSTALL a new CJB. TEST the system for normal operation.