Pinpoint Test T: An Individual Fog Lamp Is Inoperative

WARNING: This page is about a different car, the 2010 Mercury Milan, 2010 Lincoln MKZ, and 2010 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

T1 CHECK FOR VOLTAGE TO THE FOG LAMP
- Ignition OFF.
- Disconnect: Inoperative Fog Lamp.
- Ignition ON.
- Place the headlamp switch in the PARKING LAMPS ON position and engage the fog lamp switch.
- For Fusion or Milan, measure the voltage between the LH fog lamp C152-A, circuit CLF12 (BN/YE), harness side and ground; or between the RH fog lamp C162-A, circuit CLF12 (BN/YE), harness side and ground.
  
  Fig 1: Measuring Voltage Between LH Fog Lamp C152-A & Ground
  Courtesy of FORD MOTOR CO.
- For MKZ, measure the voltage between the LH fog lamp C152-1, circuit CLF12 (BN/YE), harness side and ground; or between the RH fog lamp C162-1, circuit CLF12 (BN/YE), harness side and ground.
  
  Fig 2: Measuring Voltage Between LH Fog Lamp C152-1 & Ground
  Courtesy of FORD MOTOR CO.
- Is the voltage greater than 10 volts?
- Yes: REPAIR circuit GD121 (BK/YE) (LH fog lamp) or circuit GD123 (BK/GY) (RH fog lamp) for an open. TEST the system for normal operation.
- No: REPAIR circuit CLF12 (BN/YE) for an open. TEST the system for normal operation.