LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Hummer >> 2003 >> H2 >> Repair and Diagnosis >> Electrical >> Charging Systems >> Generators & Regulators >> System Tests >> Test A: Charging System Test
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Test A: Charging System Test

NOTE: Ensure battery is in good condition before proceeding with charging system tests. See BATTERY TESTING & INSPECTION  under ON-VEHICLE TESTING.
  1. If diagnostic system check was not performed, perform ENGINE ELECTRICAL DIAGNOSTIC SYSTEM CHECK  under ON-VEHICLE TESTING. If diagnostic system check was performed, go to next step.
  2. Start engine and observe charge indicator on Instrument Panel Cluster (IPC) or message in Driver Information Center (DIC). If charge indicator illuminates or DIC displays a charging system message, go to next step. If charge indicator light does not illuminate or DIC does not display a charging system message, repair by symptom. See SYMPTOM INDEX  table.
    3. NOTE: Green POWER light of tester should remain illuminated while tester is being used.
  3. Turn ignition switch to OFF position. Using CS Generator Tester (J-41450-B), connect Red lead to generator output terminal (BAT) and Black lead to metal generator housing. If Green POWER light does not illuminate, go to next step. If Green POWER light illuminates, go to step  6 .
  4. Using a DVOM, measure voltage between output terminal (BAT) of generator and metal generator housing. If battery voltage exists, go to step  14 . If battery voltage does not exist, go to next step.
  5. Measure voltage between generator output terminal and battery negative terminal. If battery voltage exists, go to step  12 . If battery voltage does not exist, go to step  11 .
    6. CAUTION: Ensure load is completely turned off before connecting or disconnecting carbon pile load tester to battery.
  6. Connect carbon pile tester to battery. Connect inductive ammeter to output circuit of generator. Disconnect generator harness connector. Locate matching harness connector on CS Generator Tester (J-41450-B) and connect to generator. If Red DIAGNOSTIC light illuminates, go to next step. If Red DIAGNOSTIC light does not illuminate, go to step  13 .
  7. Increase engine speed to 2500 RPM. If Red DIAGNOSTIC light does not illuminate, go to next step. If Red DIAGNOSTIC light illuminates, go to step  15 .
    8. NOTE: If generator is not capable of producing Load Test amps, operate generator at maximum possible output.
  8. Maintain engine speed at 2500 RPM. Turn on load of carbon pile tester and increase load until load is equal to test value of generator. See GENERATOR SPECIFICATIONS  . If Red DIAGNOSTIC light illuminates, go to step  15 . If Red DIAGNOSTIC light does not illuminate, go to next step.
  9. Maintain engine speed at 2500 RPM and continue to operate generator at load test value. See GENERATOR SPECIFICATIONS  . Using a DVOM, measure voltage drop between generator output terminal and positive battery terminal. If voltage drop is 0.5 volt or less, go to next step. If voltage drop is greater than 0.5 volt, go to step  11 .
  10. Maintain engine speed at 2500 RPM and continue to operate generator at load test value. See GENERATOR SPECIFICATIONS  . Using a DVOM, measure voltage drop between generator metal housing and negative battery terminal. If voltage drop is 0.5 volt or less, go to step  16 . If voltage drop is greater than 0.5 volt, go to step  12 .
  11. Repair open or high resistance in generator output circuit. See WIRING DIAGRAMS  . After repair, go to step  16 .
  12. Repair open or high resistance in generator ground circuit. See WIRING DIAGRAMS  . After repair, go to step  16 .
  13. Disconnect Generator Tester harness connector, but leave alligator clips connected so Green POWER light remains illuminated. Connect a jumper with a 100 ohm in-line resistor between generator connector terminal "B" and ground. If Red DIAGNOSTIC light illuminates, go to step  15 . If Red DIAGNOSTIC light does not illuminate, go to next step.
  14. If a problem exists with CS Generator Tester (J-41450-B). Refer to manufacturer's instructions, how to test generator tester for proper operation. If tester has been repaired or replaced, go to step  3 .
  15. Replace generator. See GENERATOR  under REMOVAL & INSTALLATION. After repair, go to next step.
  16. Operate system to verify repair. If system is not operating correctly, repeat test beginning at step  3 .
Fig 1: Identifying Generator 4-Pin Connector Terminals
G00050227Courtesy of GENERAL MOTORS CORP.
scientia non olet · About LEMON Manuals