Generator On-Vehicle Tests
GENERATOR ON-VEHICLE TESTSCAUTION:
- To prevent damage to the generator, do not make the jumper wire connections except as directed.
- Do not allow any metal object to come in contact with the housing and the internal diode cooling fins with key ON or OFF. A short circuit may result and burn out the diodes.
NOTE:
- The battery posts and cable clamps must be clean and tight for accurate meter indications.
- Refer to the battery tester manual for complete directions for testing the charging system.
1. Turn off all lamps and electrical components.
2. Place the vehicle in NEUTRAL and apply the parking brake.
3. Carry out the Load Test and No-Load Test according to the following component tests:
Generator On-Vehicle Tests - Load Test
1. Switch the tester to the ammeter function.
2. Connect the positive and negative leads of the battery tester to the corresponding battery terminals.
3. Connect the current probe to the generator B+ output terminal, circuit 38 (BK/OG).
4. With the engine running at approximately 2,000 rpm, adjust the tester load bank to determine the output of the generator. The generator output should be at least 87 amps.
5. With the engine running, turn the A/C on (if equipped), 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 - No Load Test.
- If the voltage increases as specified, the charging system is operating normally.
Generator On-Vehicle Tests - 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 approximately 2,000 rpm, check the generator output voltage. The voltage should be between 13.0 and 15.0 volts. If not, GO to Symptom Chart or refer to the pinpoint test. Diagnosis By Symptom - Single Generator Pinpoint Tests - Single Generator