Undercharged Battery

This condition can result in slow cranking, or a battery indicator that is clear with a red dot showing battery is undercharged. Blue with a red dot shows battery is properly charged. A low state of charge can occur even if the charge indicator is functioning properly.

Preliminary Checks
1. Inspect drive belt for proper tension.
2. Clean and tighten battery cables and connections.
3. Ensure accessories are turned off, dome light, parking lights, etc.
4. Check wiring for damage or grounds.

Fig. 2 Charging Circuit Wiring Diagram:

No-load Test
All accessories must be off and battery fully charged prior to performing this procedure.
1. Connect voltmeter between alternator (B) terminal and battery ground terminal.
2. Connect ammeter between alternator (B) terminal and battery (+) terminal.
3. Run engine from idle up to 2000 RPM and read both meters.
4. Readings should not exceed 10 amps and 14.4-15.0 volts at 68°F. Readings will vary with regulator housing temperature, Fig. 2.
5. If voltage or current reading exceeds specification, check the alternator brush ground.

Load-test
All accessories must be off and battery fully charged prior to performing this procedure.
1. Connect voltmeter between alternator (B) terminal and battery ground terminal.
2. Connect ammeter between alternator (B) terminal and battery (+) terminal.
3. Run engine from idle up to 2000 RPM, then turn headlights and blower motor On.
4. Read ammeter. If reading is lower than 20 amps, alternator must be repaired or replaced.