Charging System Troubleshooting

Ford Ranger Charging System Troubleshooting Guide

Having charging system problems with your Ford Ranger? This guide will help you diagnose common issues such as a dead battery, alternator failure, dim lights, or a charging warning light that won’t go out.

The charging system consists of the battery, alternator, voltage regulator, wiring, and drive belt. When one of these components fails, it can cause poor charging, overcharging, or a complete electrical failure.

Use the symptom-based troubleshooting sections and chart below to quickly identify the problem and determine the correct fix.

Common Charging System Symptoms

• Battery will not hold a charge
• Battery keeps going dead overnight
• Charging/alternator warning light stays on
• Warning light does not come on at all
• Dim or flickering headlights
• Electrical accessories not working properly
• Whining or squealing noise from the alternator

Battery Will Not Hold a Charge (Possible Causes)

1. Alternator drive belt defective or not adjusted properly.
2. Electrolyte level low or battery discharged.
3. Battery terminals loose or corroded
4. Alternator not charging properly
5. Loose, broken or faulty wiring in the charging circuit.
6. Short in the vehicle wiring causing a continuous drain on the battery.
7. Battery defective internally.

Ignition light fails to go out

1. Fault in the alternator or charging circuit
2. Alternator drive belt defective or not properly adjusted

Charging Warning Light Stays On

1. Instrument cluster warning light bulb defective
2. Alternator faulty
3. Fault in the instrument cluster printed circuit, dashboard wiring or bulb holder

Charging System Problem Diagnosis Chart

The following chart lists common charging system problems, their causes, and recommended solutions.

Problem	Cause	Solution
Noisy Alternator	Loose mountings Loose drive pulley Worn bearings Brush noise Internal circuits shorted (high pitched whine)	Tighten mounting bolts Tighten pulley Replace alternator Replace alternator Replace alternator
Squeal when starting engine or accelerating	Glazed or loose belt	Replace or adjust belt
Indicator light remains on or: ammeter indicates discharge (engine running	Broken belt Broken or disconnected wires Internal alternator problems Defective voltage regulator	Install belt Replace or correct wiring Replace alternator Replace voltage regulator / alternator
Car light bulbs continually burn out Battery needs water continually	Alternator/ regulator overcharging	Replace voltage regulator / alternator
Car lights flare on acceleration	Battery low Internal alternator / regulator problems	Charge of replace battery Replace alternator / regulator
Low voltage output (Alternator light or ammeter needle flickers)	Loose or worn belt Dirty or corroded connections Internal alternator / regulator problems	Replace or adjust belt Clean or replace connections Replace alternator / regulator

 

Quick Charging System Test

You can perform a basic charging system test with a voltmeter:

• Engine off: Battery should read about 12.6 volts
• Engine running: Voltage should be 13.5 to 14.5 volts

If voltage is below or above this range, the alternator or voltage regulator may be faulty.

For more information on your charging system and how to check it, check out: Charging System – Information, Precautions & Checking

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