LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Mercury >> 2009 >> Sable Base, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1020 (Interior Lighting System) >> Diagnostic Tests >> Interior Lighting >> Pinpoint Tests >> Pinpoint Test K: The Ambient Lighting Is Inoperative >> Pinpoint Test K: The Ambient Lighting Is Inoperative
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Pinpoint Test K: The Ambient Lighting Is Inoperative

WARNING: This page is about a different car, the 2008 Mercury Mariner and 2008 Ford Escape. 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.
  1. K1 CHECK CIRCUIT CBX07 (GN/RD) FOR AN OPEN (TO AMBIENT LIGHTING MODULE) 
    • Key in OFF position.
    • Disconnect: Ambient Lighting Module C3251
    • Key in ON position.
    • Measure the voltage between the ambient lighting module C3251-1, circuit CBX07 (GN/RD), harness side and ground.
      • Fig 1: Measuring Voltage
      GF0040660Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  K2.
    2. NO  : VERIFY the SJB fuse 5 (10A) is OK. If OK, REPAIR the circuit. TEST the system for normal operation.
  2. K2 CHECK THE INPUT FROM CIRCUIT CLN54 (BN/YE) 
    • While pressing and releasing the ambient lighting switch, measure the voltage between the ambient lighting module C3251-2, circuit CLN54 (BN/YE), harness side and ground.
      • Fig 2: Measuring Voltage
      GF0040661Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts with the switch pressed and 0 volts with the switch released? 
    1. YES  : Go to  K3.
    2. NO  : If voltage is always present, go to  K4.

      If no voltage is present, go to  K5.

  3. K3 CHECK CIRCUIT GD908 (BK) FOR AN OPEN 
    • Key in OFF position.
    • Measure the resistance between the ambient lighting module C3251-8, circuit GD908 (BK), harness side and ground.
      • Fig 3: Measuring Resistance
      GF0040662Courtesy of FORD MOTOR CO.
    • Is the resistance less than 5 ohms? 
    1. YES  : Go to  K7.
    2. NO  : REPAIR the circuit. TEST the system for normal operation.
  4. K4 CHECK CIRCUIT CLN54 (BN/YE) FOR A SHORT TO VOLTAGE 
    • Key in OFF position.
    • Disconnect: Ambient Lighting Switch C3250
    • Key in ON position.
    • Measure the voltage between the ambient lighting module C3251-2, circuit CLN54 (BN/YE), harness side and ground.
      • Fig 4: Measuring Voltage
      GF0040661Courtesy of FORD MOTOR CO.
    • Is any voltage present? 
    1. YES  : REPAIR the circuit. TEST the system for normal operation.
    2. NO  : INSTALL a new ambient lighting switch. REFER to Ambient Lighting Switch . TEST the system for normal operation.
  5. K5 CHECK CIRCUIT CBX07 (GN/RD) FOR AN OPEN (TO AMBIENT LIGHTING SWITCH) 
    • Key in OFF position.
    • Connect: Ambient Lighting Module C3251
    • Disconnect: Ambient Lighting Switch C3250
    • Key in ON position.
    • Measure the voltage between the ambient lighting switch C3250-2, circuit CBX07 (GN/RD), harness side and ground.
      • Fig 5: Checking Circuit CBX07 (GN/RD) For An Open (To The Ambient Lighting Switch)
      GF0041654Courtesy of FORD MOTOR CO.
    • Is the voltage greater than 10 volts? 
    1. YES  : Go to  K6.
    2. NO  : REPAIR the circuit. TEST the system for normal operation.
  6. K6 CHECK THE AMBIENT LIGHTING SWITCH 
    • Connect and remove a fused (5A) jumper wire between the ambient lighting switch C3250-2, circuit CBX07 (GN/RD), harness side and the ambient lighting switch C3250-6, circuit CLN54 (BN/YE), harness side.
      • Fig 6: Checking Ambient Lighting Switch
      GF0042733Courtesy of FORD MOTOR CO.
    • Do the ambient LEDs illuminate and cycle through a color change each time the jumper wire is connected and removed? 
    1. YES  : INSTALL a new ambient lighting switch. REFER to Ambient Lighting Switch . TEST the system for normal operation.
    2. NO  : REPAIR circuit CLN54 (BN/YE) for an open. TEST the system for normal operation.
  7. K7 CHECK THE AMBIENT LIGHTING HARNESS 
    • Key in OFF position.
    • Check any of the diode circuits between the ambient lighting module, harness side as follows:
      Connector-Pin/Circuit Connector-Pin/Circuit
      C3251-5
      CLN45 (GN)      		 C3251-4
      RLN44 (BN)
      C3251-6
      CLN46 (BU)      		 C3251-4
      RLN44 (BN)
      C3251-7
      CLN44 (OG)      		 C3251-4
      RLN44 (BN)
      • Fig 7: Checking Diode Circuits
      GF0040665Courtesy of FORD MOTOR CO.
    • Does the meter indicate the circuit is good? 
    1. YES  : Go to  K8.
    2. NO  : REPAIR or INSTALL a new ambient lighting harness. TEST the system for normal operation.
  8. K8 CHECK FOR CORRECT AMBIENT LIGHTING MODULE OPERATION 
    • Disconnect the ambient lighting module connector.
    • Check for:
      • corrosion
      • damaged pins
      • pushed-out pins
    • Connect the ambient lighting module connector and make sure it seats correctly.
    • Operate the system and verify the concern is still present.
    • Is the concern still present? 
    1. YES  : INSTALL a new ambient lighting module. REFER to Ambient Lighting Module . TEST the system for normal operation.

      If the concern is still present, INSTALL the original ambient lighting module. INSTALL a new ambient lighting harness. 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.
scientia non olet · About LEMON Manuals