Pinpoint Test R: The Roof Marker Lamps Are Inoperative

WARNING: This page is about a different car, the 2005 Ford Pickup, 2005 Ford F550 Super Duty, 2005 Ford F450 Super Duty, and 2005 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

R1 CHECK CIRCUIT 57 (BK) FOR AN OPEN
- Disconnect: Inoperative Roof Marker Lamp.
- Measure the resistance between inoperative roof marker lamp circuit 57 (BK) and ground.
  
  Fig 1: Checking Circuit 57 (BK) For Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to R2.
- No : REPAIR the circuit. TEST the system for normal operation.
R2 CHECK CIRCUIT 14 (BN) FOR AN OPEN
- Turn the headlamp switch to the parking lamps ON position.
- Measure the voltage between inoperative roof marker lamp circuit 14 (BN), harness side and ground.
  
  Fig 2: Checking Circuit 14 (BN) For Open
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : INSTALL a new roof marker lamp assembly. REFER to LAMP ASSEMBLY - CAB MARKER LAMPS . TEST the system for normal operation.
- No : REPAIR the circuit. TEST the system for normal operation.