Pinpoint Test D: One Low Beam Headlamp Is Inoperative

D1 CHECK THE VOLTAGE AT BJB FUSE 16 OR 17
- Key in ON position.
- Place the headlamp switch in the headlamps ON position.
- Measure the voltage between the BJB fuse 16 (10A) (LH low beam), input side and ground; or between the BJB fuse 17 (10A) (RH low beam), input side and ground.
  
  Fig 1: Checking Voltage At BJB Fuse 16 Or 17
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to D2.
- No : REPAIR or INSTALL a new BJB. TEST the system for normal operation.
D2 CHECK THE VOLTAGE AT THE LOW BEAM
- Key in OFF position.
- Disconnect: Inoperative Headlamp.
- Key in ON position.
- Measure the voltage between the LH headlamp C1021-7, circuit 15S-LE16 (GN/OG), harness side and ground; or between the RH headlamp C1041-7, circuit 15S-LE23 (GN/WH), harness side and ground.
  
  Fig 2: Checking Voltage At Low Beam
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes : GO to D3.
- No : REPAIR the circuit in question. TEST the system for normal operation.
D3 CHECK THE HEADLAMP GROUND CIRCUIT
- Measure the resistance between the LH headlamp C1021-4, circuit 31-LE31 (BK), harness side and ground; or between the RH headlamp C1041-4, circuit 31-LE30 (BK), harness side and ground.
  
  Fig 3: Checking Headlamp Ground Circuit
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : REPAIR or INSTALL a new headlamp assembly. REFER to HEADLAMP ASSEMBLY . TEST the system for normal operation.
- No : REPAIR the headlamp ground circuit. TEST the system for normal operation.