Ford F150 Pickup. Manual - part 686

Fig. 15: Disconnecting Starter Motor Connections 
Courtesy of FORD MOTOR CO. 

7. Remove the cables. 

 

2003 Ford Pickup F150 

2003 ELECTRICAL Battery, Mounting and Cables - F150 Pickup

  

Fig. 16: Removing Ground Cables 
Courtesy of FORD MOTOR CO. 

8. To install, reverse the removal procedure. 

 

2003 Ford Pickup F150 

2003 ELECTRICAL Battery, Mounting and Cables - F150 Pickup

  

2003 STARTING & CHARGING SYSTEMS

Generators & Regulators - F150 Pickup 

DESCRIPTION 

System consists of generator, voltage regulator, voltage gauge, battery, fuses and associated wiring. On all 
models except 5.4L Lightning, voltage regulator is fastened to rear of alternator with brush holder assembly. On 
5.4L Lightning models, voltage regulator is an integral part of generator. On all models, voltage regulator 
incorporates temperature compensation circuitry, so battery charging voltage is maintained at the optimum 
level. Charging system voltage is maintained within an operating range of 13-15 volts. 

Warning indicator should illuminate with ignition on, engine off. Warning indicator should not illuminate with 
ignition off, or with engine running. 

ADJUSTMENTS 

BELT TENSION 

Vehicles are equipped with automatic drive belt tensioner. Drive belt does not require adjustment. Inspect 
condition and tension of generator drive belt prior to performing any on-vehicle charging system tests. Replace 
belt and/or repair tensioner mechanism if necessary. 

TROUBLE SHOOTING 

Ensure connections at generator, regulator and engine ground are clean and tight. Ensure battery posts and 
cables are clean and tight. Inspect drive belt. Inspect battery junction box fuse No. 11 (20-amp). Inspect central 
junction box fuse No. 30 (30-amp). Inspect fusible links. Check all connections for looseness or corrosion. If 
problem is found, repair as necessary. If problem is not found, see SYSTEM TESTS . 

ON-VEHICLE TESTING 

NOTE:

For trouble shooting charging system, see BASIC TROUBLE SHOOTING article 
in GENERAL INFORMATION.

CAUTION: To prevent damage to generator, do not make jumper wire connections 

except as directed.

CAUTION: Do not allow any metal object to come in contact with housing and internal 

diode cooling fans with ignition on or off. A short circuit will result and 
burn out diodes.

NOTE:

Battery posts and cable clamps must be clean and tight for accurate meter 
indications.

 

2003 Ford Pickup F150 

2003 STARTING & CHARGING SYSTEMS Generators & Regulators - F150 Pickup

  

 

2003 Ford Pickup F150 

2003 STARTING & CHARGING SYSTEMS Generators & Regulators - F150 Pickup

  

BATTERY TEST WITH DIGITAL BATTERY ANALYZER 

Connect digital battery analyzer to battery and follow on screen manuals. If battery test good, return to 
service. If battery does not test good, replace battery. 

BATTERY DRAIN TEST 

1. Ensure junction box/fuse panels are accessible without turning on interior and hood lights. Drive vehicle 

over 30 MPH for at least 5 minutes. Park vehicle and allow to sit with ignition off for at least 40 minutes 
to allow electronic modules to power down. Go to next step.  

2. Connect a fused jumper wire between negative battery cable and negative battery post. Disconnect 

negative battery cable from negative battery post, without breaking the jumper wire connection to prevent 
modules from resetting. Go to next step. 

3. Ensure ammeter is set to read milliamps with at least a 10-amp capability. Connect ammeter between 

negative battery cable and negative battery post. Remove fused jumper wire. Go to next step.  

4. If excessive current draw is present, pull fuses from battery/central junction box one at a time and note 

any current drop when each fuse is removed. DO NOT reinstall fuses until test is complete. Go to next 
step.  

5. Check wiring diagrams for any circuits that run from battery without passing through battery/central 

junction box. Disconnect these circuits if current draw still exists.  

BATTERY DRAINS THAT SHUT OFF WHEN BATTERY CABLE IS DISCONNECTED TEST 

1. Perform battery drain test. See BATTERY DRAIN TEST . Ensure all doors are closed and accessories 

are off. Without starting engine, turn ignition switch to RUN position for a moment, and then turn 
ignition OFF. Wait a few minutes for illuminated entry lamps to turn off (if equipped).  

2. Connect ammeter between negative battery cable and negative battery post. Disconnect negative battery 

cable from negative battery post, without breaking the ammeter connection to prevent modules from 
resetting. Read amperage draw.  

3. Amperage draw should be less than 50 milliamps. If current draw exceeds 50 milliamps, remove fuses 

from battery/central junction box one at a time to locate problem circuit.  

GENERATOR LOAD TEST 

1. Ensure drive belt is in good condition. Replace belt as necessary. If belt is okay, connect charging system 

load tester in accordance with manufacturer's manuals. Start and run engine at 2000 RPM, and apply 
load until generator output levels off. Generator amperage should be at least 58 amps (F150 Pickup) or 87 

NOTE:

Before performing on-vehicle testing, turn off all accessories and lights. Place 
vehicle in Neutral and apply parking brake.

NOTE:

It is very important that continuity is not broken between negative battery 
post and negative battery cable when disconnecting battery cable or 
connecting ammeter. If continuity is broken, go to step 1 .

 

2003 Ford Pickup F150 

2003 STARTING & CHARGING SYSTEMS Generators & Regulators - F150 Pickup