Ford Mustang (1999-2004) Service Manual: Reversing Lamps

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

Special Tool(s)

73III Automotive Meter or equivalent 105-R0057

Inspection and Verification

1. Verify the customer concern by operating the reversing lamps.

2. Visually inspect for obvious signs of mechanical and electrical damage; refer to the following chart:

Visual Inspection Chart

Mechanical Electrical
  • Damaged digital transmission range (DTR) sensor (automatic transmission [A/T])
  • Damaged reversing lamp switch (manual transmission [M/T])
  • Blown central junction box (CJB) Fuse 11 (15A)
  • Damaged wiring harness
  • Loose or corroded connections
  • Damaged reversing lamp
  • Damaged DTR sensor (automatic transmission [A/T])
  • Damaged reversing lamp switch (manual transmission [M/T])

3. If the concern is not visually evident, determine the symptom and proceed to Symptom Chart.

Symptom Chart

Condition Possible Sources Action
  • The reversing lamps are inoperative
  • CJB Fuse 11 (15A).
  • Bulbs.
  • Circuitry.
  • DTR sensor (A/T).
  • Reversing lamp switch (M/T).
  • GO to Pinpoint Test R .
  • The individual reversing lamp is inoperative
  • Bulb.
  • Circuitry.
  • GO to Pinpoint Test S .
  • The reversing lamps are on continuously
  • Circuitry.
  • DTR sensor (A/T).
  • Reversing lamp switch (M/T)
  • GO to Pinpoint Test T

Pinpoint Tests

PINPOINT TEST R: THE REVERSING LAMPS ARE INOPERATIVE

Test Step Result / Action to Take
R1 CHECK THE VOLTAGE TO THE DTR SENSOR (A/T) OR THE REVERSING LAMP SWITCH (M/T) Yes

GO to R2 .

No

REPAIR the circuit. TEST the system for normal operation.
  • Key in OFF position.
  • Disconnect: DTR Sensor C167 (A/T).
  • Disconnect: Reversing Lamp Switch C169 (M/T).
  • Key in ON position.
  • If equipped with A/T, measure the voltage between DTR sensor C167 Pin 9, Circuit 1087 (OG), harness side and ground.

  • If equipped with M/T, measure the voltage between reversing lamp switch C169, Circuit 1087 (OG), harness side and ground.

  • Is the voltage greater than 10 volts?
R2 CHECK CIRCUIT 140 (BK/PK) FOR OPEN Yes

INSTALL a new DTR sensor (A/T) or reversing lamp switch (M/T);  TEST the system for normal operation.

No

GO to R3 .
  • Key in OFF position.
  • If equipped with A/T, measure the resistance between DTR sensor C167 Pin 11, Circuit 140 (BK/PK), harness side and ground.

  • If equipped with M/T, measure the resistance between reversing lamp switch C169, Circuit 140 (BK/PK), harness side and ground.

  • Is the resistance less than 5 ohms?
R3 CHECK REVERSING LAMPS GROUND Yes

REPAIR Circuit 140 (BK/PK) for open. TEST the system for normal operation.

No

REPAIR the circuit. TEST the system for normal operation
  • Disconnect: Inoperative Reversing Lamp.
  • Measure the resistance between LH reversing lamp C451, Circuit 1205 (BK), or RH reversing lamp C461, Circuit 1205 (BK), harness side and ground.

  • Is the resistance less than 5 ohms?

PINPOINT TEST S: THE INDIVIDUAL REVERSING LAMP IS INOPERATIVE

Test Step Result / Action to Take
S1 CHECK REVERSING LAMPS GROUND Yes

REPAIR Circuit 140 (BK/PK) for open.

TEST the system for normal operation.

No

REPAIR the circuit.

TEST the system for normal operation.
  • Key in OFF position.
  • Disconnect: Inoperative Reversing Lamp.
  • Measure the resistance between LH reversing lamp C451, Circuit 1205 (BK), or RH reversing lamp C461, Circuit 1205 (BK), harness side and ground.

  • Is the resistance less than 5 ohms?

PINPOINT TEST T: THE REVERSING LAMPS ARE ON CONTINUOUSLY

Test Step Result / Action to Take
T1 CHECK THE CONTINUITY OF THE DTR SENSOR (A/T) OR THE REVERSING LAMP SWITCH (M/T) Yes

REPAIR Circuit 140 (BK/PK) for short to battery.

TEST the system for normal operation.

No

INSTALL a new DTR sensor (A/T) or reversing lamp switch (M/T); TEST the system for normal operation.
  • Key in OFF position.
  • Disconnect: DTR Sensor C167 (A/T).
  • Disconnect: Reversing Lamp Switch C169 (M/T).
  • Set the parking brake.
  • Key in ON position.
  • Select REVERSE.
  • Are the reversing lamps illuminated?
    Fog Lamps
    Refer to Wiring Diagrams Cell 86 , Fog Lamps for schematic and connector information. Special Tool(s) 73 III Automotive Meter or equivalent 105-R0057 Principles of Operation The f ...

    Headlamp Adjustment
    Headlamp Aiming 1. The headlamp aiming procedure depends on the type of beam pattern the headlamp is equipped with. Vehicles may come equipped with visual optical right (VOR), visual optical lef ...

    Other materials:

    Air Bag Supplemental Restraint System (SRS) (Diagnosis and Testing)
    Refer to Wiring Diagrams Cell 46 , Air Bag for schematic and connector information. Special Tool(s) Diagnostic Tool, Restraint System 418-F088 (105-R0012) Restraint System Diagnostic Tool Warning WARNING: This tool is for restraint system se ...

    Spark Plug - Inspection
    1. Inspect the spark plug for a bridged gap. Check for deposit build-up closing the gap between the electrodes. Deposits are caused by oil or carbon fouling. Clean the spark plug. 2. Check for oil fouling. Check for wet, black deposits on th ...

    Installing child seats
    Child Seats Use a child safety seat (sometimes called an infant carrier, convertible seat, or toddler seat) for infants, toddlers or children weighing 40 pounds (18 kilograms) or less (generally age four or younger). Using Lap and Shoulder Belts WARNING: Airb ...