Preliminary Diagnosis

NOISE DIAGNOSIS
Noise from a generator may be caused by a loose drive pulley, loose mounting bolts, worn or dirty bearings, faulty diode or faulty stator.

To avoid damage to electrical equipment, always observe the following precautions:
- Do not reverse connections to the generator.
- Do not short across or ground any of the terminals in the charging circuit, except as directed by the instructions.
- Never operate the generator with the output terminal disconnected.

Trouble in the charging system will show up as one or more of the following conditions:
a. Faulty indicator lamp operation. Some vehicles have a voltmeter instead of an indicator lamp. The needle on the voltmeter indicates system voltage. If the needle stays at or near either end of the gage, there may be a problem in the charging system.
b. An undercharged battery, as shown by slow cranking or a dark hydrometer in the battery.
c. An overcharged battery, as shown by spewing of electrolyte from the vents.

CHARGING SYSTEM - CS DIAGNOSIS

TOOL REQUIRED:
- J 39200 Multimeter

When operating normally, the indicator lamp will come on when the switch is turned on, then go out when the engine starts. If the indicator does not work properly, or if the battery is over or undercharged, use the following procedure to diagnose the charging system. Remember that an undercharged battery is often caused by accessories being left on overnight, or by a defective switch that allows a lamp (such as a trunk lamp) to stay on.

Use the following procedure to diagnose the CS-130 and CS13OD charging system:

IMPORTANT: The battery must be in a fully charged condition before attempting any charging system testing procedures.

1. Check the serpentine drive belt and wiring.
2. For vehicles without a charge indicator lamp, go to Step 5.
3. With ignition switch "0n", engine stopped, lamp should be on. If not, detach harness electrical connector at generator and ground "L" terminal.
a. Lamp lights, repair or replace the generator.
b. Lamp does not light, locate open circuit between grounding lead and ignition switch. Lamp may be open.

4. With ignition switch "On", engine running at moderate speed, lamp should be off. If not, detach wiring harness electrical connector at generator.
a. If lamp goes off, replace the generator.
b. If lamp stays on, check for grounded "L" terminal wire in harness.

5. Battery undercharged or overcharged.
a. Detach wiring harness electrical connector from generator.
b. With ignition switch "On", engine not running, connect voltmeter, J 39200 (or equivalent), from ground to "L" terminal in harness.
c. Zero reading indicates open circuit between terminal and battery. Correct as required.
d. Reconnect harness electrical connector to generator, start and run engine at moderate speed.
e. Measure voltage across battery. If above 16V, check "S" terminal circuit (if used) for high resistance or intermittent connection. Clean and tighten all connections. If generator still operates above 16V, replace generator.
f. Place current clamp, J 35590, around the generator output lead and turn on accessories, load battery with carbon pile to obtain maximum amperage. Maintain voltage at 13V or above.
g. If within 15 amperes of rated output, generator is okay.
h. If not within 15 amperes of rated output, replace the generator.