2014 Mustang Workshop Manual

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

Reversing 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

The PCM monitors the transmission gear status. When the PCM detects the transmission is in REVERSE (R), the PCM sends a message to the Body Control Module B (BCM-B). When the BCM-B receives this message, it provides voltage to the reversing lamps.

Inspection and Verification

Verify the customer concern.

Visually inspect for obvious signs of electrical damage.

Visual Inspection Chart

Electrical
Bulb Wiring, terminals or connectors Rear lamp jumper harness

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.

Clear the continuous DTCs and carry out the self-test diagnostics for the PCM and Body Control Module B (BCM-B).

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 .

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

Symptom Chart

Symptom Chart
Condition	Possible Sources	Action
All the reversing lamps are inoperative	Wiring, terminals or connectors Reversing lamps switch (manual transmission) PCM BCM-B	VERIFY the bulbs are OK. If OK, GO to Pinpoint Test W .
An individual reversing lamp is inoperative	Wiring, terminals or connectors Rear lamp jumper harness	VERIFY the bulbs are OK. If OK, GO to Pinpoint Test X .
The reversing lamps are on continuously	Wiring, terminals or connectors Reversing lamps switch (manual transmission) Auto-dimming interior mirror PCM	GO to Pinpoint Test Y .

Pinpoint Tests

Pinpoint Test W: All The Reversing Lamps Are Inoperative

Refer to Wiring Diagrams Cell 11 , Fuse and Relay Information for schematic and connector information.

Refer to Wiring Diagrams Cell 93 , Reversing Lamps for schematic and connector information.

Normal Operation

When the Body Control Module B (BCM-B) receives a message from the PCM indicating the transmission is in reverse, the BCM-B supplies voltage to the reversing lamps.

Automatic Transmission

The PCM monitors the gear status from the transmission. When the transmission is in REVERSE (R), a message is sent to the BCM-B . If any gear status concerns exist, the PCM sets a DTC and the wrench indicator turns on.

Manual Transmission

The PCM sends a voltage signal to the reversing lamps switch. When the transmission is in REVERSE (R), the voltage signal is routed back to the PCM and the PCM sends a message to the BCM-B indicating the transmission is in reverse.

DTC B1277:11 (Reverse Lamp: Circuit Short To Ground) — sets when the BCM-B detects a short to ground from one of the reversing lamp output circuits.

DTC B1277:15 (Reverse Lamp: Circuit Short To Battery or Open) — sets when the BCM-B detects an open from both reversing lamp output circuits.

This pinpoint test is intended to diagnose the following:

Wiring, terminals or connectors
Reversing lamps switch (manual transmission)
PCM
BCM-B

PINPOINT TEST W: ALL THE REVERSING LAMPS ARE 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
W1 CARRY OUT THE BCM-B REVERSING LAMP CONTROL ACTIVE COMMAND USING THE SCAN TOOL
Ignition ON. Enter the following diagnostic mode on the scan tool: BCM-B DataLogger. Select the BCM-B reversing lamp (REVERSE_LMP) active command. Command the reversing lamp on and off. Do the reversing lamps turn on when commanded on?	Yes GO to W7 . No GO to W2 .
W2 CHECK FOR THE BCM-B REVERSE LAMP SHORT TO GROUND DTC
Ignition OFF. Review the results from the BCM-B self-test. Is DTC B12772:11 present?	Yes GO to W4 . No GO to W3 .
W3 CHECK THE STOPLAMP OPERATION
Apply and release the brake pedal while observing the stoplamps. Do the stoplamps operate correctly?	Yes GO to W11 . No REFER to Stoplamps in this section.
W4 ISOLATE THE LH REAR LAMP SHORT TO GROUND
Disconnect: LH Rear Lamp C498. Ignition ON. Enter the following diagnostic mode on the scan tool: BCM-B Self-Test. Clear the DTCs and repeat the self-test (required to enable the stoplamp output driver if DTC U1000:00 is present) . Is DTC B12772:11 still present?	Yes GO to W5 . No REPAIR or INSTALL a new LH rear lamp jumper harness. TEST the system for normal operation.
W5 ISOLATE THE RH REAR LAMP SHORT TO GROUND
Ignition OFF. Disconnect: RH Rear Lamp C499. Ignition ON. Enter the following diagnostic mode on the scan tool: BCM-B Self-Test. Clear the DTCs and repeat the self-test (required to enable the stoplamp output driver if DTC U1000:00 is present) . Is DTC B12772:11 still present?	Yes GO to W6 . No REPAIR or INSTALL a new RH rear lamp jumper harness. TEST the system for normal operation.
W6 CHECK THE BCM-B REVERSE LAMP OUTPUT CIRCUITS FOR A SHORT TO GROUND
Ignition OFF. Disconnect: BCM-B C4368a. Measure the resistance between the LH rear lamp C498-1, circuit CLS10 (GN/BN), harness side and ground; and between the RH rear lamp C499-1, circuit CLS11 (GY/VT), harness side and ground. Are the resistances greater than 10,000 ohms?	Yes GO to W11 . No REPAIR the circuit in question for a short to ground. After the repair: If no DTCs are present, TEST the system for normal operation. If DTC U1000:00 is present, CLEAR the DTCs and REPEAT the self-test (required to enable the stoplamp output driver) . TEST the system for normal operation. If DTC U3000:49 is present, INSTALL a new SJB . REFER to Section 419-10 . TEST the system for normal operation.
W7 CHECK FOR PCM DTCs
Ignition ON. Disconnect: PCM Self-Test. Carry out the PCM Key ON Engine OFF (KOEO) and Key ON Engine Running (KOER) self-tests. Are any PCM DTCs present?	Yes REFER to Section 419-10 or the Powertrain Control/Emissions Diagnosis (PC/ED) manual as necessary. No For vehicles with an automatic transmission, REFER to Section 307-01 to diagnose a Transmission Range (TR) input concern. For vehicles with a manual transmission, GO to W8 .
W8 BYPASS THE REVERSING LAMP SWITCH
Ignition OFF. Disconnect: Reversing Lamp Switch C169 (3.7L or 5.0L engine) or C1131 (5.8L engine). For vehicles with a 3.7L or 5.0L engine, connect a fused jumper wire between the reversing lamp switch C169-1, circuit CET47 (BU), harness side and the reversing lamp switch C169-2, circuit RE405 (GN/WH), harness side. For vehicles with a 5.8L engine, connect a fused jumper wire between the reversing lamp switch C1131-A, circuit CET47 (BU), harness side and the reversing lamp switch C1131-B, circuit RE405 (GN/WH), harness side. Ignition ON. Do the reversing lamps illuminate?	Yes REMOVE the jumper wire. INSTALL a new reversing lamp switch. REFER to Reversing Lamp Switch in this section. TEST the system for normal operation. No REMOVE the jumper wire. GO to W9 .
W9 CHECK THE REVERSING LAMP SWITCH INPUT
Ignition OFF. Connect: Reversing Lamp Switch C169 (3.7L or 5.0L engine) or C1131 (5.8L engine). Disconnect: PCM C1381t (3.7L engine) or C175t (5.0L or 5.8L engine) . Select REVERSE. For vehicles with a 3.7L engine, measure the resistance between the PCM C1381t-17, circuit CET47 (BU), harness side and the PCM C1381t-41, circuit RE406 (GY/VT), harness side. For vehicles with a 5.0L or 5.4L engine, measure the resistance between the PCM C175t-7, circuit CET47 (BU), harness side and the PCM C175t-38, circuit RE406 (GY/VT), harness side. Is the resistance less than 3 ohms?	Yes GO to W12 . No GO to W10 .
W10 CHECK THE REVERSING LAMP SWITCH CIRCUITS FOR AN OPEN
Disconnect: Reversing Lamp Switch C169 (3.7L or 5.0L engine) or C1131 (5.8L engine). For vehicles with a 3.7L engine, measure the resistance between the PCM C1381t-17, circuit CET47 (BU), harness side and the reversing lamp switch C169-1, circuit CET47 (BU), harness side. For vehicles with a 5.0L engine, measure the resistance between the PCM C175-7, circuit CET47 (BU), harness side and the reversing lamp switch C169-1, circuit CET47 (BU), harness side. For vehicles with a 5.8L engine, measure the resistance between the PCM C175-7, circuit CET47 (BU), harness side and the reversing lamp switch C1131-A, circuit CET47 (BU), harness side. Is the resistance less than 3 ohms?	Yes REPAIR circuit RE406 (GY/VT) for an open. TEST the system for normal operation. No REPAIR circuit CET47 (BU) for an open. TEST the system for normal operation.
W11 CHECK FOR CORRECT BCM-B OPERATION
Disconnect all the BCM-B connectors. Check for: corrosion damaged pins pushed-out pins Connect all the BCM-B 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 BCM-B . 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.
W12 CHECK FOR CORRECT PCM OPERATION
Disconnect all the PCM connectors. Check for: corrosion damaged pins pushed-out pins Connect all the PCM 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 PCM. REFER to Section 303-14 . 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 X: An Individual Reversing Lamp Is Inoperative

Refer to Wiring Diagrams Cell 93 , Reversing Lamps for schematic and connector information.

When the Body Control Module B (BCM-B) receives a message from the PCM indicating the transmission is in reverse, the BCM-B supplies voltage to the reversing lamps.

This pinpoint test is intended to diagnose the following:

Wiring, terminals or connectors
Rear lamp jumper harness
BCM-B

PINPOINT TEST X: AN INDIVIDUAL REVERSING LAMP 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
X1 CHECK FOR VOLTAGE TO THE REVERSING LAMP
Ignition OFF. Disconnect: Inoperative Rear Lamp. Ignition ON. Apply the parking brake. Select REVERSE. Measure the voltage between the LH rear lamp C498-1, circuit CLS10 (GN/BN), harness side and ground; or between the RH rear lamp C499-1, circuit CLS11 (GY/VT), harness side and ground. Is the voltage greater than 11 volts?	Yes REPAIR or INSTALL a new rear lamp jumper harness. TEST the system for normal operation. No GO to X2 .
X2 CHECK THE REVERSING LAMP VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
Ignition OFF. Measure the resistance between the LH reversing lamp C498-1, circuit CLS10 (GN/BN), harness side and between the BCM-B C4368a-5, circuit CLS10 (GN/BN), harness side: or between the RH reversing lamp C499-1, circuit CLS11 (GY/VT), harness side and between the BCM-B C4368a-17, circuit CLS11 (GY/VT), harness side. Is the resistance less than 3 ohms?	Yes GO to X3 . No REPAIR circuit CLS10 (GN/BN) or CLS11 (GY/VT) for an open. TEST the system for normal operation.
X3 CHECK FOR CORRECT BCM-B OPERATION
Disconnect all the BCM-B connectors. Check for: corrosion damaged pins pushed-out pins Connect all the BCM-B 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 BCM-B . 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.

Pinpoint Test Y: The Reversing Lamps Are On Continuously

Refer to Wiring Diagrams Cell 93 , Reversing Lamps for schematic and connector information.

Normal Operation

When the Body Control Module B (BCM-B) receives a message from the PCM indicating the transmission is in reverse, the BCM-B supplies voltage to the reversing lamps.

Automatic Transmission

Manual Transmission

DTC B1277:15 (Reverse Lamp: Circuit Short To Battery or Open) — sets when the BCM-B detects a short to voltage from one of the reversing lamp output circuits.

This pinpoint test is intended to diagnose the following:

Wiring, terminals or connectors
Reversing lamp switch (manual transmission)
BCM-B
PCM

PINPOINT TEST Y: THE REVERSING 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
Y1 CHECK FOR BCM-B DTC B1272:15
Ignition OFF. Review the results from the BCM-B self-test. Is DTC B1272:15 present?	Yes GO to Y2 . No GO to Y3 .
Y2 CHECK THE BCM-B REVERSING LAMP OUTPUT CIRCUITS FOR A SHORT TO VOLTAGE
Ignition OFF. Disconnect: BCM-B C4368a. Ignition ON. Do the reversing lamps continue to illuminate?	Yes REPAIR circuit CLS10 (GN/BN) (LH reverse lamp) or circuit CLS11 (GY/VT) (RH reverse lamp) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. No GO to Y6 .
Y3 CHECK FOR PCM DTCs
Ignition ON. Disconnect: PCM Self-Test. Carry out the PCM Key ON Engine OFF (KOEO) and Key ON Engine Running (KOER) self-tests. Are any PCM DTCs present?	Yes REFER to Section 419-10 or the Powertrain Control/Emissions Diagnosis (PC/ED) manual as necessary. No For vehicles with an automatic transmission, REFER to Section 307-01 to diagnose a Transmission Range (TR) input concern. For vehicles with a manual transmission, GO to Y4 .
Y4 CHECK THE REVERSING LAMP SWITCH
Ignition OFF. Disconnect: Reversing Lamp Switch C169 (3.7L or 5.0L engine) or C1131 (5.8L engine). Ignition ON. Do the reversing lamps continue to illuminate?	Yes GO to Y5 . No INSTALL a new reversing lamp switch. REFER to Reversing Lamp Switch in this section. TEST the system for normal operation.
Y5 CHECK THE REVERSING LAMP SWITCH INPUT CIRCUIT FOR A SHORT TO GROUND
Ignition OFF. Disconnect: PCM C1381t (3.7L engine) or C175t (5.0L or 5.8L engine) . For vehicles with a 3.7L or 5.0L engine, measure the resistance between the reversing lamp switch C169-1, circuit CET47 (BU), harness side and ground. For vehicles with a 5.8L engine, measure the resistance between the reversing lamp switch C1131-A, circuit CET47 (BU), harness side and ground. Is the resistance greater than 10,000 ohms?	Yes GO to Y7 . No REPAIR circuit CET47 (BU) for a short to ground. TEST the system for normal operation.
Y6 CHECK FOR CORRECT BCM-B OPERATION
Disconnect all the BCM-B connectors. Check for: corrosion damaged pins pushed-out pins Connect all the BCM-B 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 BCM-B . 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.
Y7 CHECK FOR CORRECT PCM OPERATION
Disconnect all the PCM connectors. Check for: corrosion damaged pins pushed-out pins Connect all the PCM 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 PCM. REFER to Section 303-14 . 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.