Generator On-Vehicle Tests

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

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





90 Amp Generator





130 Amp Generator

Load Test
1. Switch Alternator, Regulator, Battery and Starter Tester (ARBST) to the ammeter function.
2. Connect the positive and negative leads of ARBST to the battery.
3. Connect the current probe to the generator B+ output lead, circuit 36 (Y/W).
4. With the engine running at 2000 RPM, adjust ARBST load bank to determine the output of the generator. Compare generator output with the graphs shown. If not, refer to the Symptom Chart for diagnostic procedures. Symptom Related Diagnostic Procedures

No-Load Test
1. Switch Alternator, Regulator, Battery and Starter Tester (ARBST) to the voltmeter function.
2. Connect the 73 Digital Multimeter 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 2000 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