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Home >> Mercury >> 2010 >> Milan Base, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 1106 (Interior Lighting) >> Diagnostic Tests >> Interior Lighting >> Pinpoint Tests >> Pinpoint Test I: The Courtesy Lamps Are Inoperative From The Headlamp Switch >> Pinpoint Test I: The Courtesy Lamps Are Inoperative From The Headlamp Switch

Pinpoint Test I: The Courtesy Lamps Are Inoperative From The Headlamp Switch

WARNING: This page is about a different car, the 2008 Ford RV Cutaway, 2008 Ford Econoline, 2008 Ford E450 Super Duty, and 2008 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
  1. I1 VERIFY THE VEHICLE CHASSIS TYPE 
    • Verify the vehicle chassis type.
    • Is the vehicle a stripped chassis? 
    1. YES  : Go to  I2.
    2. NO  : Go to  I4.
  2. I2 CHECK CIRCUIT 54 (LG/YE) FOR AN OPEN 
    • Key in OFF position.
    • Disconnect: Headlamp Switch C205
      • Fig 1: Checking Circuit 54 (LG/YE) For An Open
      GF0012937Courtesy of FORD MOTOR CO.
    • Measure the voltage between the headlamp switch C205-8, circuit 54 (LG/YE), harness side and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  I3.
    2. NO  : VERIFY the CJB fuse 4 (15A) is OK. If OK, REPAIR the circuit. TEST the system for normal operation.
  3. I3 CHECK CIRCUIT 53 (BK/LB) FOR AN OPEN 
      Fig 2: Checking Circuit 53 (BK/LB) For An Open
      GF0012938Courtesy of FORD MOTOR CO.
    • Connect a fused (5A) jumper wire between the headlamp switch C205-8, circuit 54 (LG/YE), harness side and the headlamp switch C205-7, circuit 53 (BK/LB), harness side.
    • Do the courtesy lamps illuminate? 
    1. YES  : REMOVE the jumper wire. INSTALL a new headlamp switch. REFER to EXTERIOR LIGHTING article. TEST the system for normal operation.
    2. NO  : REMOVE the jumper wire. REPAIR the circuit. TEST the system for normal operation.
  4. I4 CHECK CIRCUIT 402 (OG/LG) FOR AN OPEN 
    • Key in OFF position.
    • Disconnect: Headlamp Switch C205
      • Fig 3: Checking Circuit 402 (OG/LG) For An Open
      GF0012937Courtesy of FORD MOTOR CO.
    • Measure the voltage between the headlamp switch C205-8, circuit 402 (OG/LG), harness side and ground.
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  I5.
    2. NO  : REPAIR the circuit. TEST the system for normal operation.
  5. I5 CHECK CIRCUIT 938 (BK/LG) FOR AN OPEN 
      Fig 4: Checking Circuit 938 (BK/LG) For An Open
      GF0012938Courtesy of FORD MOTOR CO.
    • Connect a fused (5A) jumper wire between the headlamp switch C205-8, circuit 402 (OG/LG), harness side and the headlamp switch C205-7, circuit 938 (BK/LG), harness side.
    • Do the courtesy lamps illuminate? 
    1. YES  : REMOVE the jumper wire. Go to  I6.
    2. NO  : REMOVE the jumper wire. REPAIR the circuit. TEST the system for normal operation.
  6. I6 CHECK THE HEADLAMP SWITCH 
    • Carry out the component test for the headlamp switch. Refer to COMPONENT TESTING.
    • Is the headlamp switch OK? 
    1. YES  : Go to  I7.
    2. NO  : INSTALL a new headlamp switch. REFER to EXTERIOR LIGHTING article. TEST the system for normal operation.
  7. I7 CHECK FOR CORRECT IC OPERATION 
    • Key in OFF position.
    • Disconnect all the IC connectors.
    • Check for:
      • corrosion
      • damaged pins
      • pushed-out pins
    • Connect all the IC connectors and make sure they seat correctly.
    • Operate the system and verify the concern is still present.
    • Is the concern still present? 
    1. YES  : INSTALL a new IC. REFER to INSTRUMENT CLUSTER (IC) AND WARNING CHIMES article. TEST the system for normal operation.
    2. NO  : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
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