Flow of Diagnosis

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 S0LUTION. 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.
- 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.
- 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.

NOTE:
- Before performing charging system tests on the vehicle, note the complaint (such as slow cranking, battery discharged, indicator lamp on). This information will aid in isolating which part of the system is causing the symptom.
- Only test the charging system with a fully charged, properly operating battery. Check the testing equipment and instructions. If the testing equipment is malfunctioning or the instructions for use are incorrect, use the equipment on a vehicle known to be operating properly.

Troubleshooting or diagnosis is required before actual service can be made in the electrical system. Even where an obvious condition makes replacement of a component necessary, find out why the component failed. When a condition is diagnosed correctly, unnecessary service is prevented, the time the vehicle is out of service will be decreased, and the condition will be fixed right the first time.

Perform a visual inspection using this procedure:
1. Check battery posts and battery cable terminals for clean and tight connections. Remove the battery cables (if corroded); clean and install them securely.
2. Check for clean and tight wiring connections at the Generator (GEN), Voltage Regulator (VR) and engine.
3. Check the drive belt tension.
4. Check the battery state of charge.

Isolating the Concern
Isolate the battery, the charging system, and the electrical circuits to correctly identify the area where the difficulty lies. Check the battery before performing any electrical system diagnosis. The battery must be in the proper state of charge and operation before other areas of the electrical system can perform normally.

Open circuits or other wiring concerns can prevent the generator from operating normally.

Battery Check
Check the battery to see if it can accept and hold a charge; refer to the battery capacity tests. Battery Capacity Test

If the battery is good, then the charging system should be checked to see that it can keep the battery charged.

The battery capacity test will determine the ability of a battery to accept and hold a charge. If the battery cannot meet the specifications, replace it with a new fully charged battery before further diagnosis.

If the battery meets the required specifications, it should be fully charged before proceeding with the diagnosis of other electrical system components.

Drain Testing
Refer to Drain Testing Test. Drain Testing

These are some of the most common current drain problems:
- Interior lamp stays on continuously.
- Electronic component malfunctions.

Generator Check
Check the generator to see if it is producing the proper output current and voltage. Refer to the generator component tests. Generator Testing

If the generator does not meet specifications, use the Symptom Chart to determine the correct test procedure for troubleshooting the charging system. Symptom Related Diagnostic Procedures

Visual Inspection Chart

Mechanical
- Battery
- Generator drive belt
- Generator pulley

Electrical
- Battery charge
- Blown fuse:
- 100 A MAIN
- 30 A FUEL INJ
- 10 A METER
- 15 A METER
- Damaged, loose or corroded electrical connections
- Charging system indicator
- Other electrical systems malfunctions

1. If an obvious cause for malfunction is found, correct the cause before proceeding to the next step.
2. If fault is not visually evident, determine the symptom and proceed to the Symptom Chart. Symptom Related Diagnostic Procedures