Ford Mustang (1999-2004) Service Manual: Inspection and Verification

WARNING: Batteries contain sulfuric acid. Avoid contact with skin, eyes, or clothing.

Also, shield your eyes when working near batteries to protect against possible splashing of the acid solution. In case of acid contact with skin or eyes, flush immediately with water for a minimum of 15 minutes and get prompt medical attention. If acid is swallowed, call a physician immediately.

WARNING: Batteries normally produce explosive gases which can cause personal injury.

Therefore, do not allow flames, sparks or lighted substances to come near the battery. When charging or working near a battery, always shield your face and protect your eyes. Always provide ventilation.

WARNING: When lifting a plastic-cased battery, excessive pressure on the end walls could cause acid to spew through the vent caps resulting in personal injury, damage to the vehicle or to the battery. Lift with a battery carrier or with your hands on opposite corners.

1. Verify the customer concern by operating the engine to duplicate the concern.

2. Inspect the charging system (battery, generator cable, harness connectors, connections) to determine if any obvious mechanical or electrical concerns exist. If found, repair as necessary and test the system for normal operation. Refer to the following tables:

Visual Inspection Chart

Mechanical Electrical
  • Battery case, posts, hold-down clamp, cables and connections
  • Generator drive (serpentine) belt for condition and tension. Refer to Section.
  • Generator pulley
  • Battery junction box (BJB) fuse 20 (20A)
  • Fuse links
  • Circuitry
  • Battery charge warning indicator
  • Cables

3. Check the operation of the charging system warning indicator lamp (instrument cluster). Normal operation is as follows:

  • With the ignition switch OFF, the charging system warning indicator should be OFF.
  • With the ignition switch in RUN and the engine off, the charging system warning indicator light should be on.
  • With the engine running, the charging system warning indicator light should be off.

4. Verify the battery is being charged. Carry out the Battery-Load Test. Refer to Component Tests in this section.

Normal Charging System Voltages

Normal Charging System Voltages

5. If the customer concern is verified after the initial inspection, refer to the Symptom Chart to determine which tests to carry out.

Symptom Chart

Condition Possible Sources Action
  • Battery is discharged or voltage is low
  • Circuitry.
  • High key-off current drain(s).
  • Battery.
  • Generator.
  • Go To Pinpoint Test A .
  • The charging system warning indicator is on with the engine running (the system voltage does not increase)
  • Circuitry.
  • Voltage regulator.
  • Generator.
  • Go To Pinpoint Test B .
  • The system overcharges (the battery voltage is greater than 15.5 volts)
  • Circuitry.
  • Voltage regulator.
  • Generator.
  • Go To Pinpoint Test C .
  • The charging system warning indicator is on with the engine running and the battery increases voltage
  • Circuitry.
  • Instrument cluster.
  • Voltage regulator.
  • Generator.
  • Go To Pinpoint Test D
  • The charging system warning indicator is off with the ignition switch in the RUN position and the engine off
  • Bulb.
  • Circuitry.
  • Instrument cluster.
  • Voltage regulator.
  • Generator.
  • Go To Pinpoint Test E
  • The charging system warning indicator flickers or is intermittent
  • Central junction box (CJB) fuse 5 (15A).
  • Generator connector unplugged (C102a).
  • Circuitry.
  • Generator.
  • Go To Pinpoint Test F .
  • The generator is noisy
  • Bolts or brackets.
  • Drive belt.
  • Generator or pulley.
  • Go To Pinpoint Test G .
  • Radio interference
  • Generator.
  • Circuitry.
  • In-vehicle entertainment system.
  • Go To Pinpoint Test F .
    Functionality
    With the ignition switch in the RUN position, voltage is applied through the warning indicator I circuit 904 (LG/RD) to the voltage regulator. This turns the regulator on, allowing current to ...

    Pinpoint Tests
    CAUTION: Do not make jumper connections except as directed. Incorrect connections may damage the voltage regulator test terminals, fuses, or fuse links. CAUTION: Do not allow any metal object ...

    Other materials:

    Stub Shaft Pilot Bearing and Seal
    Special Tool(s) Remover, Bearing Cup 308-047 (T77F-1102-A) Protector, Differential Seal (Pair) 205-461 Installer, Differential Oil Seal 205-293 (T89P-4850-A) Adapter for 303-224 (Handle) 205-153 (T80T-4000-W) ...

    Anti-theft system
    The active anti-theft system is designed to warn you in the event of unauthorized vehicle entry and is also designed to help prevent unwanted towing of the vehicle. You can choose what is monitored by arming the system in different ways. Partial Monitor Mode ...

    Valve Tappets
    Material Removal CAUTION: If removing more than one valve tappet, mark the components removed for correct location. 1. Remove the lower intake manifold. For additional information, refer to Lower Intake Manifold in this section. 2. Remove the push r ...