SECTION 417-01: Exterior Lighting
2014 Mustang Workshop Manual
DIAGNOSIS AND TESTING
Procedure revision date: 01/07/2013

Parking, Rear and License Plate Lamps


Special Tool(s)
Fluke 77-IV Digital Multimeter
FLU77-4 or equivalent
Vehicle Communication Module (VCM) and Integrated Diagnostic System (IDS) software with appropriate hardware, or equivalent scan tool
Flex Probe Kit
105-R025D or equivalent
 

Principles of Operation

NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).

The SJB monitors the headlamp switch position by sending voltage signals on multiple circuits to the headlamp switch. There is one circuit for each headlamp switch position. At any given time, one of the signal circuits is switched to ground.

If the SJB does not detect any of the inputs to the headlamp switch is active (switched to ground) for 5 seconds, the SJB turns the parking lamps and headlamps on and keeps them on until the battery saver feature times out.

Additionally, if the SJB detects multiple headlamp switch input circuits short to ground, the SJB turns the parking lamps and headlamps on and keeps them on until the battery saver feature times out.

Refer to Exterior Lighting for information regarding the Battery Saver feature.

If the above situation occurs, the SJB cannot be ruled immediately as being at fault. This is normal behavior of the SJB design as it has detected a fault with the inputs from the headlamp switch.

 

Inspection and Verification

  1. Verify the customer concern.
  1. Visually inspect for obvious signs of mechanical or electrical damage.


  Visual Inspection Chart

Mechanical Electrical
  • Headlamp switch
  • Smart Junction Box (SJB) fuse 22 (15A)
  • Bulb holder
  • Wiring, terminals or connectors
  • Rear lamp jumper harness
  • LED lamp
  • SJB

  1. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.

  1. NOTE: Make sure to use the latest scan tool software release.

    If the cause is not visually evident, connect the scan tool to the Data Link Connector (DLC).

  1. NOTE: The Vehicle Communication Module (VCM) LED prove-out confirms power and ground from the DLC are provided to the VCM .

    If the scan tool does not communicate with the VCM :
  1. If the scan tool does not communicate with the vehicle:
  1. Carry out the network test.
  1. Clear the continuous DTCs and carry out the self-test diagnostics for the SJB .
  1. If the DTCs retrieved are related to the concern, go to the Diagnostic Trouble Code (DTC) Chart in this section. For all other DTCs, refer to the Diagnostic Trouble Code (DTC) Chart in Section 419-10 .
  1. If no DTCs related to the concern are retrieved, GO to Symptom Chart .
 

Symptom Chart

 
Symptom Chart
Condition Possible Sources Action
  • One or more parking, rear or license plate lamps is inoperative
  • Fuse
  • Wiring, terminals or connectors
  • Bulb holder
  • LED lamp
  • Rear lamp jumper harness
  • Headlamp assembly
  • Smart Junction Box (SJB)
  • The parking, rear or license plate lamps are on continuously
  • Wiring, terminals or connectors
  • Headlamp switch
  • SJB
 

Pinpoint Tests

 

Pinpoint Test Q: One Or More Parking, Rear or License Plate Lamps Is Inoperative

Refer to Wiring Diagrams Cell 92 , Parking, Rear and License Lamps for schematic and connector information.

Normal Operation

When the headlamp switch is placed in the PARKING LAMPS ON position, the Smart Junction Box (SJB) energizes the parking lamp relay coil (integrated into the SJB ). When the parking lamp relay is energized, voltage is routed to the rear and front parking lamps.

This pinpoint test is intended to diagnose the following:

 
PINPOINT TEST Q: ONE OR MORE PARKING, REAR OR LICENSE PLATE LAMPS IS INOPERATIVE

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

Test Step Result / Action to Take
  Q1 DETERMINE IF ALL THE PARKING LAMPS ARE INOPERATIVE  
  • Ignition OFF.
  • Place the headlamp switch in the PARKING LAMPS ON position.
  • Are all the parking lamps inoperative?
Yes
PLACE the headlamp switch in the OFF position. VERIFY the SJB fuse 22 (15A) is OK. If OK, GO to Q6 . If not OK, REFER to the Wiring Diagrams Manual to identify the possible causes of the circuit short.

No
If all the front parking lamps are inoperative, GO to Q2 .

If all the rear parking and license plate lamps are inoperative, GO to Q3 .

For all others, GO to Q4 .
  Q2 CHECK THE SJB PARKING LAMP OUTPUT CIRCUIT FOR AN OPEN (FRONT LAMPS)  
  • Disconnect: SJB C2280e.
  • Connect a fused jumper wire between the SJB C2280e-1, circuit CE612 (GY/VT), harness side and the SJB C2280e-6, circuit CLS30 (VT/WH), harness side.


  • Ignition ON.
  • Do the front parking lamps illuminate?
Yes
REMOVE the jumper wire. GO to Q7 .

No
REMOVE the jumper wire. REPAIR circuit CLS30 (VT/WH) for an open. TEST the system for normal operation.
  Q3 CHECK THE SJB PARKING LAMP OUTPUT CIRCUIT FOR AN OPEN (REAR LAMPS)  
  • Disconnect: SJB C2280d.
  • Connect a fused jumper wire between the positive battery terminal and the SJB C2280d-20, circuit CLS30 (VT/WH), harness side.


  • Do the rear parking lamps illuminate?
Yes
REMOVE the jumper wire. GO to Q7 .

No
REMOVE the jumper wire. REPAIR circuit CLS30 (VT/WH) for an open. TEST the system for normal operation.
  Q4 CHECK FOR VOLTAGE TO THE INOPERATIVE LAMP  
  • Disconnect: Inoperative Lamp.
  • Place the headlamp switch in the PARKING LAMPS ON position.
  • Measure the voltage between the inoperative lamp, harness side and ground as follows:


    • Inoperative Lamp Connector-Pin Circuit
    LH front C1509-5 CLS30 (VT/WH)
    RH front C1510-5 CLS30 (VT/WH)
    LH front side marker C151-1 CLS30 (VT/WH)
    RH front side marker C161-1 CLS30 (VT/WH)
    LH rear side marker C481-1 CLS30 (VT/WH)
    RH rear side marker C482-1 CLS30 (VT/WH)
    LH license plate C4046b-2 CLS30 (VT/WH)
    RH license plate C4046a-2 CLS30 (VT/WH)
    LH rear lamp C498-2 CLS30 (VT/WH)
    RH rear lamp C499-2 CLS30 (VT/WH)



  • Is the voltage greater than 11 volts?
Yes
GO to Q5 .

No
REPAIR circuit CLS30 (VT/WH) for an open. TEST the system for normal operation.
  Q5 CHECK THE VOLTAGE TO THE INOPERATIVE LAMP USING THE CONNECTOR GROUND  
  • Measure the voltage between the inoperative lamp connector, harness side as follows:


    • Inoperative Lamp Connector-Pin/ Circuit Connector-Pin/ Circuit
    LH front C1509-5

    CLS30 (VT/WH)     		C1509-8

    GD129 (BK/YE)
    LH front C1509-5

    CLS30 (VT/WH)     		C1509-14

    GD123 (BK/GY)
    RH front C1510-5

    CLS30 (VT/WH)     		C1510-8

    GD123 (BK/GY)
    RH front C1510-5

    CLS30 (VT/WH)     		C1510-14

    GD129 (BK/YE)
    LH front side marker C151-1

    CLS30 (VT/WH)     		C151-2

    GD129 (BK/YE)
    RH front side marker C161-1

    CLS30 (VT/WH)     		C161-2

    GD129 (BK/YE)
    LH rear side marker C481-1

    CLS30 (VT/WH)     		C481-2

    GD110 (BK/YE)
    RH rear side marker C482-1

    CLS30 (VT/WH)     		C482-2

    GD110 (BK/YE)
    LH license plate C4046b-1

    CLS30 (VT/WH)     		C4046b-2

    GD110 (BK/YE)
    RH license plate C4046a-1

    CLS30 (VT/WH)     		C4046a-2

    GD110 (BK/YE)
    LH rear lamp C498-2

    CLS30 (VT/WH)     		C498-6

    GD109 (BK)
    RH rear lamp C499-2

    CLS30 (VT/WH)     		C499-6

    GD110 (BK/WH)



  • Is the voltage greater than 11 volts?
Yes
For any side marker or license plate lamp, INSTALL a new bulb holder. TEST the system for normal operation.

For any front lamp, INSTALL a headlmap assembly. REFER to Headlamp Assembly . TEST the system for normal operation.

For a rear lamp, GO to Q6 .

No
REPAIR the ground circuit in question for an open. TEST the system for normal operation.
  Q6 CHECK THE REAR LAMP JUMPER HARNESS  
  • Place the headlamp switch in the OFF position.
  • Inspect the rear lamp jumper harness for opens.
  • Is the rear lamp jumper harness OK?
Yes
INSTALL a new LED lamp. TEST the system for normal operation.

No
REPAIR or INSTALL a new rear lamp jumper harness. TEST the system for normal operation.
  Q7 CHECK FOR CORRECT SJB OPERATION  
  • Disconnect all the SJB connectors.
  • Check for:
    • corrosion
    • damaged pins
    • pushed-out pins
  • Connect all the SJB connectors and make sure they seat correctly.
  • Operate the system and verify the concern is still present.
  • Is the concern still present?
Yes
INSTALL a new SJB . REFER to Section 419-10 . TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
 

Pinpoint Test R: The Parking, Rear Or License Plate Lamps Are On Continuously

Refer to Wiring Diagrams Cell 92 , Parking, Rear and License Lamps for schematic and connector information.

Normal Operation

The Smart Junction Box (SJB) monitors the parking lamp request input from the headlamp switch. The SJB provides a ground for the parking lamp relay coil (integrated into the SJB ) when a request for the parking lamps is received. When the parking lamp relay is energized, voltage is routed to the rear and front parking lamps.

This pinpoint test is intended to diagnose the following:

 
PINPOINT TEST R: THE PARKING, REAR OR LICENSE PLATE LAMPS ARE ON CONTINUOUSLY

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

Test Step Result / Action to Take
  R1 USE THE RECORDED DTCs FROM THE SJB SELF-TEST  
  • Check the recorded results from the SJB self-test.
  • Was DTC B1578 recorded?
Yes
GO to R2 .

No
GO to R4 .
  R2 CHECK FOR A VOLTAGE SIGNAL TO THE HEADLAMP SWITCH  
  • Ignition OFF.
  • Disconnect: Headlamp Switch C205.
  • Measure the voltage between the headlamp switch C205-2, circuit CLS34 (GY), harness side and ground.


  • Is the voltage greater than 11 volts?
Yes
INSTALL a new headlamp switch. REFER to Headlamp Switch in this section. CLEAR the DTCs. REPEAT the self-test.

No
GO to R3 .
  R3 CHECK THE PARKING LAMP REQUEST INPUT CIRCUIT FOR A SHORT TO GROUND  
  • Disconnect: SJB C2280b.
  • Measure the resistance between the headlamp switch C205-2, circuit CLS34 (GY), harness side and ground.


  • Is the resistance greater than 10,000 ohms?
Yes
GO to R6 .

No
REPAIR circuit CLS34 (GY) for a short to ground. CLEAR the DTCs. REPEAT the self-test.
  R4 CHECK THE SJB PARKING LAMP OUTPUT CIRCUIT FOR A SHORT TO VOLTAGE (TO REAR LAMPS)  
  • Ignition OFF.
  • Disconnect: SJB C2280d.
  • Ignition ON.
  • Do the rear parking lamps continue to illuminate?
Yes
REPAIR circuit CLS30 (VT/WH) for a short to voltage. TEST the system for normal operation.

No
GO to R5 .
  R5 CHECK THE SJB PARKING LAMP OUTPUT CIRCUIT FOR A SHORT TO VOLTAGE (TO FRONT LAMPS)  
  • Ignition OFF.
  • Disconnect: SJB C2280e.
  • Ignition ON.
  • Do the front parking lamps continue to illuminate?
Yes
REPAIR circuit CLS30 (VT/WH) for a short to voltage. TEST the system for normal operation.

No
GO to R6 .
  R6 CHECK FOR CORRECT SJB OPERATION  
  • Disconnect all the SJB connectors.
  • Check for:
    • corrosion
    • damaged pins
    • pushed-out pins
  • Connect all the SJB connectors and make sure they seat correctly.
  • Operate the system and verify the concern is still present.
  • Is the concern still present?
Yes
INSTALL a new SJB . REFER to Section 419-10 . TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.