2014 Mustang Workshop Manual

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

Daytime Running Lamps (DRL)

Special Tool(s)
	Vehicle Communication Module (VCM) and Integrated Diagnostic System (IDS) software with appropriate hardware, or equivalent scan tool

Principles of Operation

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

The SJB controls the Daytime Running Lamps (DRL) by using various inputs to determine whether or not the DRL should be illuminated. These inputs include:

Ignition switch position
Headlamp switch position
Headlamps on or off
Transmission gear selection
Parking brake input status

The DRL are not a programmable parameter for this vehicle.

When the DRL is active, the SJB energizes the fog lamp relay. This illuminates the fog lamps at full intensity.

Inspection and Verification

Verify the customer concern.

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

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).

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 :
- Check the VCM connection to the vehicle.
- Check the scan tool connection to the VCM .
- Refer to Section 418-00 , No Power To The Scan Tool, to diagnose no power to the scan tool.

If the scan tool does not communicate with the vehicle:
- Verify the ignition key is in the ON position.
- Verify the scan tool operation with a known good vehicle.
- Refer to Section 418-00 to diagnose no response from the PCM.

Carry out the network test.
- If the scan tool responds with no communication for one or more modules, refer to Section 418-00 .
- If the network test passes, retrieve and record the continuous memory DTCs.

If no DTCs related to the concern are retrieved, GO to Symptom Chart .

Symptom Chart

Symptom Chart
Condition	Possible Sources	Action
The Daytime Running Lamps (DRL) are inoperative	Exterior lighting system input/output Ignition switch input Transmission gear input Parking brake input SJB	GO to Pinpoint Test Z .

Pinpoint Tests

Pinpoint Test Z: The Daytime Running Lamps (DRL) Are Inoperative

Normal Operation

When the ignition switch is in the RUN position, the headlamps are not on (from the autolamp system or manual control from the headlamp switch), the transmission is not in PARK (P) (automatic transmission), or the parking brake is not applied (manual transmission), the Smart Junction Box (SJB) provides a pulse-width modulated voltage to the low beam headlamps. This illuminates the fog lamps at full intensity.

This pinpoint test is intended to diagnose the following:

Exterior lighting system input/output
Ignition switch input
Transmission gear input (automatic transmission)
Parking brake switch input (manual transmission)
SJB

PINPOINT TEST Z: THE DRL ARE INOPERATIVE

Test Step	Result / Action to Take
Z1 VERIFY THE DRL OPERATION
Ignition ON. Place the headlamp switch in the OFF position. If equipped with an automatic transmission, place the gear selector lever in any gear other than PARK (P). If equipped with a manual transmission, release the parking brake. Are the DRL illuminated?	Yes The system is operating correctly. INFORM the customer of the conditions required for the DRL to operate correctly. No IGO to Z2 .
Z2 CHECK THE OPERATION OF THE FOG LAMPS
Place the headlamp switch in the PARKING LAMPS ON position and engage the fog lamp switch. Do the fog lamps operate correctly?	Yes GO to Z3 . No REFER to Fog Lamps in this section.
Z3 CHECK THE IGNITION SWITCH INPUT
Place the headlamp switch in the OFF position. Enter the following diagnostic mode on the scan tool: SJB DataLogger. Monitor the SJB ignition switch PIDs (IGN_A_ECU, IGN_O_ECU, IGN_R_ECU, IGN_S_ECU) while cycling the ignition switch through all positions. Does the PID agree with the ignition switch positions?	Yes For vehicles with an automatic transmission, GO to Z4 . For vehicles with a manual transmission, GO to Z5 . No REFER to Section 211-05 to diagnose the input from the ignition switch.
Z4 CHECK THE TRANSMISSION GEAR INPUT
Ignition ON. Enter the following diagnostic mode on the scan tool: PCM DataLogger. Monitor the PCM transmission gear status PID (TR) while placing the gear selector lever through all positions. Does the PID agree with the gear selection?	Yes INSTALL a new SJB . REFER to Section 419-10 . TEST the system for normal operation. No REFER to Section 307-01 to diagnose the transmission range input.
Z5 CHECK THE BRAKE WARNING INDICATOR OPERATION
Ignition ON. Apply and release the parking brake while observing the brake warning indicator. Does the brake warning indicator operate correctly?	Yes INSTALL a new SJB . REFER to Section 419-10 . TEST the system for normal operation. No REFER to Section 413-01 to diagnose the brake warning indicator.