See Figure 1
A charge indicator lamp is used in most cars to signal when there is a fault in the charging system. This lamp is located in the gauge package and is used in diagnosis. A voltmeter may be used instead of the charge indicator lamp in diagnosis.
- Check the drive belt(s) for wear and tension. Check wiring for obvious damage.
- Go to Step 7 for vehicles without a charge indicator lamp.
- With the ignition switch ON , and the engine stopped, the lamp should be ON. If not, detach the wiring harness at the alternator and ground the "L" terminal lead.
- If the lamp illuminates, replace the alternator. If the lamp does not illuminate, locate the open circuit between the grounding lead and the ignition switch. Check the lamp, it may be open.
- With the ignition switch ON and the engine running at moderate speed, the lamp should be OFF. If not, stop the engine, then turn the switch ON and detach the wiring harness at the alternator.
- If the lamp goes out, replace the alternator. If the lamp stays ON, check for a grounded "L" terminal wire in the harness.
Determine if the battery is undercharged or overcharged.
An undercharged battery is evidenced by slow cranking or a dark hydrometer.
- Detach the wiring harness connector from the alternator.
- With the ignition switch ON , and the engine not running, connect a voltmeter from ground to the "L" terminal in the wiring harness, and to the "I" terminal, if used.
- A zero reading indicated an open circuit between the terminal and the battery. Repair the circuit as necessary.
- Engage the harness connector to the alternator and run the engine at moderate speed with all accessories OFF.
- Measure the voltage across the battery. If above 16 volts, replace the alternator.
- Connect an ammeter at the alternator output terminal, run the engine at moderate speed, turn ON all the accessories and load the battery with a carbon pile to obtain maximum amperage. Maintain voltage at 13 volts or above.
- If the output is within 15 amps of the rated output of the alternator (stamped on the alternator case), the alternator is good. If the output is not within 15 amps, replace the alternator.
REMOVAL & INSTALLATION
See Figures 2, 3, 4, 5, 6, 7 and 8
- Disconnect the negative battery cable at the battery.
- Disconnect and label the two terminal plug and the battery leads from the rear of the alternator.
- Loosen the alternator mounting bolts. Push the alternator inwards, then slip the drive belt off the pulley.
- Remove the mounting bolts, then remove the alternator from the vehicle.
- Place the alternator in its brackets and install the mounting bolts. Do not tighten them yet.
- Slip the belt back over the pulley. Pull outwards on the unit and adjust the belt tension (see Routine Maintenance ). Tighten the mounting and adjusting bolts.
- Attach the electrical leads to the alternator.
- Connect the negative battery cable.