Ford F150 Pickup. Instruction — part 688

TEST C: SYSTEM OVERCHARGES (GREATER THAN 15.5 VOLTS)

1. Check For Voltage Drop In "A" Circuit (Orange/Light Blue Wire)

Disconnect generator 3-pin harness connector. Turn ignition on. Measure voltage between generator
terminal "A" (Orange/Light Blue) and positive battery terminal. If voltage is less than .5 volt, go to next
step. If voltage is .5 volt or more, repair high resistance in circuit between generator and battery.

2. Check Generator And Battery Ground Connections

Turn ignition off. Inspect generator and regulator grounds (mounting surfaces and fasteners). Inspect
battery ground. If problem exists, repair as necessary. On Lightning models, if all grounds are okay,
replace generator. See GENERATOR under REMOVAL & INSTALLATION. On all other models, if
all grounds are okay, replace voltage regulator. See VOLTAGE REGULATOR under REMOVAL &
INSTALLATION.

TEST D: WARNING INDICATOR IS ON WITH ENGINE RUNNING, SYSTEM IS CHARGING

1. Check "I" Circuit (Light Green/Red Wire) For Short To Ground

Disconnect generator 3-pin harness connector. Turn ignition on. Observe warning indicator. If warning
indicator illuminates, repair short to ground in Light Green/Red wire between generator and instrument
panel. On Lightning models, if warning indicator does not illuminate, replace generator. See
GENERATOR under REMOVAL & INSTALLATION. On all other models, if warning indicator does
not illuminate, go to next step.

2. Inspect Generator "S" Terminal

Turn ignition off. Connect generator harness connector. Check generator 1-pin harness connector for
damage, corrosion and looseness (White/Black wire). If problem does not exist, go to next step. If
problem exists, repair as necessary.

3. Check Generator For Low Voltage

Start engine and let idle. Using DVOM, backprobe and measure voltage between ground and generator 1-
pin harness connector terminal "S" (White/Black wire). See Fig. 1 . Increase engine speed to 2000 RPM.
If voltage is 5 volts or more, replace voltage regulator. See VOLTAGE REGULATOR under
REMOVAL & INSTALLATION. If voltage is less than 5 volts, replace generator. See GENERATOR
under REMOVAL & INSTALLATION.

TEST E: WARNING INDICATOR IS OFF WITH IGNITION ON

1. Check The Charging System Warning Indicator Lamp

Turn ignition off. Disconnect generator 3-pin harness connector. Connect a fused (15-amp) jumper wire

NOTE:

There are 2 terminals "S" on generator. Ensure voltage measurement is
made at 1-pin harness connector and not at 3-pin harness connector.

2003 Ford Pickup F150

2003 STARTING & CHARGING SYSTEMS Generators & Regulators - F150 Pickup

between generator harness connector terminal "I" (Light Green/Red wire) and ground. See Fig. 2 . On
Lightning models, if indicator warning light illuminates, replace generator. See GENERATOR under
REMOVAL & INSTALLATION. On all other models, if indicator warning light illuminates, replace
voltage regulator. See VOLTAGE REGULATOR under REMOVAL & INSTALLATION. On all
models, if warning indicator does not illuminate, repair warning indicator as necessary. See appropriate
ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT.

TEST F: WARNING INDICATOR FLICKERS OR OPERATES INTERMITTENTLY

1. Check For Loose Connections

Inspect all generator, power distribution and battery connections for looseness, corrosion, and loose or
bent terminals. If all connections are okay, go to next step. If a problem exists, repair as necessary.

2. Check Fuse Connections

Start engine and let idle. Inspect battery junction box fuse No. 11 (20-amp) for looseness. Inspect central
junction box fuse No. 30 (30-amp) for looseness. Wiggle fuse connections and note warning indicator. If
warning indicator does not flicker, go to next step. If warning indicator flickers, repair loose fuse
connections as necessary.

3. Check "A" Circuit (Orange/Light Blue) Connections

Turn ignition off. Using a fused (15-amp) jumper wire connected to positive battery terminal, backprobe
generator harness connector terminal No. "A" (Orange/Light Blue wire). See Fig. 2 . Start engine and let
idle. Observe warning indicator. On Lightning models, if warning indicator flickers, replace generator.
See GENERATOR under REMOVAL & INSTALLATION. On all other models, if warning indicator
flickers, go to next step. On all models, if warning indicator does not flicker, repair loose connection(s)
between generator and battery. See WIRING DIAGRAMS .

4. Inspect Generator "S" Terminal

Turn ignition off. Check generator 1-pin harness connector for damage, corrosion and looseness
(White/Black wire). If problem does not exist, go to next step. If problem exists, repair as necessary.

5. Check Generator Brushes

Turn ignition off. Remove generator from vehicle. Measure resistance between voltage regulator "F"
terminal screw on back of generator and generator 3-pin connector terminal "A" (component side). See
Fig. 1 and Fig. 3 . If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms,
replace generator. See GENERATOR under REMOVAL & INSTALLATION.

6. Check For A Grounded Slip Ring

Remove voltage regulator and brush holder. Measure resistance between generator housing and each
generator slip ring. See Fig. 4 . If resistance is 10 k/ohms or more between both slip rings and housing,
replace voltage regulator. If resistance is less than 10 k/ohms between either slip ring and housing,

2003 Ford Pickup F150

2003 STARTING & CHARGING SYSTEMS Generators & Regulators - F150 Pickup

replace generator. See GENERATOR under REMOVAL & INSTALLATION.

Fig. 4: Checking For Grounded Generator Slip Ring (Except Lightning)
Courtesy of FORD MOTOR CO.

TEST G: GENERATOR NOISY

1. Check For Accessory Drive Noise

Turn ignition off. Check accessory drive belt for damage and correct installation. Check mounting
brackets and pulleys for looseness and damage. If problem does not exist, go to next step. If problem
exists, repair as necessary.

2. Check Generator Mounting

Check generator installation. Ensure all fasteners are tight. If problem does not exist, go to next step. If
problem exists, repair as necessary.

3. Check Generator For Electrical Noise

Disconnect generator 3-pin harness connector. Start engine and let idle. Turn headlights on. Turn rear
defogger on. Turn blower motor to high speed. If noise still exists, go to next step. If noise does not still
exist, replace generator. See GENERATOR under REMOVAL & INSTALLATION.

2003 Ford Pickup F150

2003 STARTING & CHARGING SYSTEMS Generators & Regulators - F150 Pickup

4. Check Generator For Mechanical Noise

Turn ignition off. Connect generator harness connector. Start engine and let idle. Turn all accessories off.
Using a stethoscope, check generator for unusual mechanical noise. If generator is source of noise,
replace generator. See GENERATOR under REMOVAL & INSTALLATION. If generator is not source
of noise, isolate noise and repair as necessary.

TEST H: RADIO INTERFERENCE

1. Verify Generator Is Source Of Radio Interference

Start engine and let idle. Tune radio to station where interference is present. Turn ignition off. Disconnect
generator 3-pin harness connector. Start engine and let idle. If interference is still present, repair radio
concern. If interference is not still present, replace generator. See GENERATOR under REMOVAL &
INSTALLATION.

REMOVAL & INSTALLATION

GENERATOR

Removal & Installation (4.2L)

Disconnect negative battery cable. Remove drive belt from generator pulley. Disconnect generator electrical
connectors. Remove 3 mounting bolts and generator from vehicle. To install, reverse removal procedure.
Tighten fasteners to specification. See TORQUE SPECIFICATIONS .

Removal & Installation (4.6L & 5.4L 2V)

Disconnect negative battery cable. Disengage drive belt from generator pulley. Remove 3 mounting bracket
bolts. Remove generator mounting bolts and generator from vehicle. Disconnect generator electrical connectors.
To install, reverse removal procedure. Tighten fasteners to specification. See TORQUE SPECIFICATIONS .

Removal & Installation (Lightning)

Disconnect negative battery cable. Remove retaining bolt securing degas bottle and position aside. Remove
supercharger drive belt. Remove drive belt tensioner support bracket and drive belt from generator pulley.
Loosen lower generator brackets and remove upper generator bracket bolts. Disconnect generator electrical
connector from generator bracket. Remove right side generator lower mounting bolt. Remove engine bracket
bolt and 2 generator bracket bolts. Rotate generator to access voltage regulator electrical connector. Disconnect
electrical connectors and remove generator from vehicle. To install, reverse removal procedure. Tighten

CAUTION: When battery is disconnected, vehicle computer and memory systems

may lose memory data. Driveability problems may exist until computer
systems have completed a relearn cycle. See COMPUTER RELEARN
PROCEDURES - FORD article in GENERAL INFORMATION before
disconnecting battery.

2003 Ford Pickup F150

2003 STARTING & CHARGING SYSTEMS Generators & Regulators - F150 Pickup