Generator Testing

NOTE: Battery posts and cable clamps must be clean and tight for accurate meter indications.

When carrying out charging system tests, turn off all lamps and electrical components. Place transmission in NEUTRAL and apply parking brake.

Generator On-Vehicle Test - Load Test
1. Switch the tester to the ammeter function.
2. Connect the positive and negative leads of the tester to the battery.
3. Connect the current probe to the generator B+ output lead circuit.







4. With the engine running at 2,000 rpm, adjust tester load bank to determine the output of the generator. Generator output should be greater than shown on the graph. If not, refer to Symptom Chart for diagnostic procedures. Symptom Related Diagnostic Procedures
5. With the engine running, turn the A/C on, the blower motor on high speed and the headlamps on high beam.
6. Increase the engine speed to approximately 2,000 rpm. The voltage should increase a minimum of 0.5 volt above the base voltage.
^ If the voltage does not increase as specified, carry out the Generator On-Vehicle Tests.
^ If the voltage increases as specified, the charging system is operating normally.

Generator On-Vehicle Test - No-Load Test
1. Switch the tester to the voltmeter function.
2. Connect the voltmeter positive lead to the generator B+ terminal and the negative lead to ground.
3. Turn all electrical accessories off.
4. With the engine running at 2,000 rpm, check the generator output voltage. The voltage should be between 13.0 and 15.0 volts. If not, refer to the Symptom Chart for diagnostic procedures. Symptom Related Diagnostic Procedures