Diagnosis: Overview

Preliminary Information

Before performing charging or starting system tests on the vehicle, note the condition such as: slow cranking, battery dead or using an excessive amount of water, top of the battery wet, ammeter shows charge at all times and/or no charge, alternator warning lamp does not come on and/or never goes out. This information will aid in isolating the part of the system causing the symptoms.
Next, visually inspect as follows:

1. Check the fuse link located between the starter solenoid and the alternator. If it is burned, determine and/or correct the cause and replace the fuse link.

2. Check battery posts and battery cable terminals for clean and tight connections. Remove the battery cables (if corroded), clean and install them securely.

3. Check for clean and tight wiring connections at the alternator, regulator and engine.
4. Check the alternator belt tension using a belt tension gauge and tighten to specification (if necessary), as described in this Section.

Isolating the Problem

Battery, starting system, and lamp system problems can be caused by poor charging system performance. It is also possible to suspect the charging system because of an overload in another area of the electrical system.

To avoid guesswork, it is necessary to isolate the battery, the charging system and the electrical circuits to correctly identify the area where the difficulty lies. The best method to do this is to check the battery first before any electrical system diagnosis. The battery must be in proper state of charge and operating properly before other areas of the electrical system can perform normally.