Ford F150 Pickup. Instruction - part 687

amps (all others), with engine at 2000 RPM. Go to next step.

2. Turn A/C system on. Turn blower speed to high. Turn headlights on to high beams. Voltage should

increase a minimum of .5 volt. If voltage is as specified, system is operating properly at this time. If
voltage is not as specified, perform GENERATOR NO-LOAD TEST .

GENERATOR NO-LOAD TEST

Switch tester to voltmeter function. Connect voltmeter positive lead to B+ terminal on generator and negative
lead to ground. Turn all electrical accessories off. Start and run engine up to 2000 RPM. Read voltmeter when
voltage stabilizes. Voltage should be 13-15 volts. If voltage is not as specified, go to SYMPTOM INDEX table
under SYSTEM TESTS.

SYSTEM TESTS

SYMPTOM INDEX

TEST A: BATTERY IS DISCHARGED OR VOLTAGE IS LOW

1. Check The Battery Condition

Test battery condition. See BATTERY TEST WITH DIGITAL BATTERY ANALYZER under ON-
VEHICLE TESTING. If battery is okay, go to next step. If battery is not okay, replace battery.

2. Check The Generator Output

Perform generator load and no-load tests. See GENERATOR LOAD TEST and GENERATOR NO-
LOAD TEST under ON-VEHICLE TESTING. If generator is okay, go to next step. If generator is not
okay, perform TEST B: WARNING INDICATOR IS ON WITH ENGINE RUNNING, SYSTEM IS
NOT CHARGING .

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.

Symptom

Perform Test

Battery Is Discharged Or Voltage Is Low

Warning Indicator Is On With Engine Running, System Is Not Charging

System Overcharges (Greater Than 15.5 Volts)

Warning Indicator Is On With Engine Running, System Is Charging

Warning Indicator Is Off With Ignition On

Warning Indicator Flickers Or Operates Intermittently

Generator Noisy

Radio Interference

2003 Ford Pickup F150

2003 STARTING & CHARGING SYSTEMS Generators & Regulators - F150 Pickup

3. Check For Battery Drains

Perform BATTERY DRAIN TEST under ON-VEHICLE TESTING. If no excessive current draw was
not found, go to next step. If any excessive current draw was found, repair as necessary.

4. Check For Battery Drains That Shut Off When Battery Cable Is Disconnected

Perform BATTERY DRAINS THAT SHUT OFF WHEN BATTERY CABLE IS DISCONNECTED
TEST under ON-VEHICLE TESTING. If there are any current drains that shut off when the battery is
disconnected, repair as necessary. If no drains were found, perform TEST B: WARNING INDICATOR
IS ON WITH ENGINE RUNNING, SYSTEM IS NOT CHARGING .

TEST B: WARNING INDICATOR IS ON WITH ENGINE RUNNING, SYSTEM IS NOT CHARGING

1. Check Generator B+ Circuit (Black/Orange Wire)

Measure voltage between ground and generator terminal B+ (Black/Orange wire). See Fig. 1 . If battery
voltage is present, go to next step. If battery voltage is not present, repair circuit between battery and
generator. See WIRING DIAGRAMS .

2. Check Generator "A" Circuit (Orange/Light Blue Wire)

Disconnect generator 3-pin harness connector. Measure voltage between ground and generator connector
terminal "A" (Orange/Light Blue wire). See Fig. 2 . If battery voltage is present, go to next step. If battery
voltage is not present, repair circuit between battery and generator. See WIRING DIAGRAMS .

3. Check "I" Circuit (Light Green/Red Wire) For An Open

Connect generator harness connector. Start engine and let idle. Using a DVOM, backprobe between
ground and generator harness connector terminal "I" (Light Green/Red wire). See Fig. 2 . If battery
voltage is present, go to next step. If battery voltage is not present, repair Light Green/Red wire between
generator and instrument cluster. See WIRING DIAGRAMS .

4. Check For Voltage Drop In B+ Circuit (Black/Orange Wire)

Turn on headlights on. Turn rear window defogger on. Turn blower motor to high speed. Increase engine
speed to 2000 RPM. Measure voltage between positive battery terminal and generator terminal B+
(Black/Orange wire). If voltage drop is less than .5 volt, on all models except Lightning, go to next step.
On Lightning models, replace generator. See GENERATOR under REMOVAL & INSTALLATION. If
voltage drop is .5 volt or more, repair circuit between battery and generator. See WIRING
DIAGRAMS .

5. Check For A Hung Brush

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 less, replace generator. See GENERATOR under

2003 Ford Pickup F150

2003 STARTING & CHARGING SYSTEMS Generators & Regulators - F150 Pickup

REMOVAL & INSTALLATION. If resistance is 5 ohms or more, replace voltage regulator. See
VOLTAGE REGULATOR under REMOVAL & INSTALLATION.

Fig. 1: Identifying Generator Terminals
Courtesy of FORD MOTOR CO.

2003 Ford Pickup F150

2003 STARTING & CHARGING SYSTEMS Generators & Regulators - F150 Pickup

Fig. 2: Identifying Generator 3-Pin Connector Terminals
Courtesy of FORD MOTOR CO,

Fig. 3: Exploded View Of Voltage Regulator & Brush Holder (Except Lightning)
Courtesy of FORD MOTOR CO.

2003 Ford Pickup F150

2003 STARTING & CHARGING SYSTEMS Generators & Regulators - F150 Pickup

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