Pinpoint Test D: One High Beam Headlamp Is Inoperative

WARNING: This page is about a different car, the 2006 Mercury Milan, 2006 Lincoln Zephyr, and 2006 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

D1 CHECK CIRCUIT GD121 (BK/YE) (LH HEADLAMP) OR CIRCUIT GD123 (BK/GY) (RH HEADLAMP) FOR AN OPEN
- Key in OFF position.
- Disconnect: Inoperative Headlamp.
- Measure the resistance between the LH headlamp C1021-4, circuit GD121 (BK/YE), harness side and ground; or between the RH headlamp C1041-4, circuit GD123 (BK/GY), harness side and ground.
  
  Fig 1: Checking Circuit GD121 (BK/YE) (LH Headlamp) Or Circuit GD123 (BK/GY) (RH Headlamp) For Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
Yes : GO to D2.

No : REPAIR the circuit in question. TEST the system for normal operation.
D2 CHECK CIRCUIT CLS08 (VT/GN) FOR AN OPEN
- Place the headlamp switch in the HEADLAMPS ON position.
- Place the multifunction switch in the HIGH BEAM position.
- Measure the voltage between the LH headlamp C1021-7, circuit CLS08 (VT/GN), harness side and ground; or between the RH headlamp C1041-7, circuit CLS08 (VT/GN), harness side and ground.
  
  Fig 2: Checking Circuit CLS08 (VT/GN) For Open
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
Yes : REPAIR or INSTALL a new headlamp assembly. REFER to HEADLAMP ASSEMBLY . TEST the system for normal operation.

No : REPAIR the circuit. TEST the system for normal operation.