GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 41450-B J 41450-B

The following bench check may be used to verify the operation of a CS generator. Use only a test stand with known calibrated generator speed and ampere load indicators. This check simulates the operation of the generator on a vehicle. When the generator is on the vehicle and needs to be checked, refer to Generator Not Operating Properly .

  1. Mount the generator in suitable test stand according to test stand manufacturer's instructions. The test stand must be capable of driving the generator at 6500 RPM.
  2. Make sure that the test stand battery is a fully charged, 12-volt automotive battery.
  3. Turn OFF the internal or external test load, depending on the type of stand used. Connect across the battery terminals.
  4. Make sure that the internal or external ammeter is connected in series with the test stand leads. The DMM must be capable of reading up to 150 amperes.
  5. Connect the positive test stand lead to the generator output BAT terminal. Connect the negative test stand lead to the metal housing of the generator.
  6. Verify proper operation of the J 41450-B . Perform the J 41450-B self-test procedure following the manufacturer's instructions.
  7. Connect the red alligator clip of the J 41450-B to the generator output terminal and the black alligator clip to the metal generator housing. The green POWER lamp on the tester should light. If the lamp lights, go to the next step. If not, recheck the wiring for correct connections (the lamp will not light if the polarity or tester connections are reversed).
  8. Connect the matching 4-way connector on the J 41450-B to the generator. The red DIAGNOSTIC lamp should light. If the lamp lights, go to next step. If the lamp does not light, repair the generator for improper assembly or a faulty regulator.
  9. With both the red and green lamps lighted on the J 41450-B , start the test stand and slowly increase the speed. The red DIAGNOSTIC lamp on the tester should become dark before the speed reaches 2500 RPM. Increase the speed to 6500 RPM. The red lamp on the tester should remain dark. If the lamp on the tester becomes dark at lower speed, go to the next step. If the red lamp either remains lighted or lights again at the higher speed, repair the generator for either a no-output or an uncontrolled voltage condition.
  10. With the test stand driving the generator at 6500 RPM, turn on the test load and adjust to the proper load test value. Refer to Generator Usage . The red lamp on the J 41450-B should remain dark:
  11. • If the lamp remains dark, the generator is GOOD and should be returned to service.
    • If the red lamp lights with the test load at or below the specified value, repair the generator for a low output condition.
    • If the load test amperes value cannot be reached and the red lamp does not come on, check the test stand load bank for low ampere capacity.
  12. Turn the test load OFF and stop the test stand. Disconnect ground load from the generator housing before disconnecting the test lead from the generator output BAT terminal.