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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 422 (Engine Controls - System & Component Testing - 3.8L) >> Relays & Solenoids >> Ignition Relay (BONNEVILLE, Grand PRIX, Impala & Monte CARLO) >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2003 Pontiac Grand Prix, 2003 Pontiac Bonneville, 2003 Chevrolet Monte Carlo, 2003 Chevrolet Impala, and 2003 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: The ignition relay diagnostic procedure assumes that the vehicle battery is fully charged.
  1. Perform Diagnostic System Check - Engine Controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. After performing Diagnostic System Check - Engine Controls, go to next step.
  2. Turn ignition switch to RUN position, engine OFF. Remove the underhood bottom junction block cover. Probe the following fuses using the test light connected to a good ground:
    • Eng Devices
    • Oxy sensors
    • DFI/MDL
    • Trans SOL
    • A/C relay fuse
    • Fuel INJ

    Does the test light illuminate on at least one test point of each fuse? If yes, go to next step. If no, go to step  11.

  3. Turn ignition switch to OFF position. Probe both test points of the FUEL INJ fuse using a test light connected to a good ground. Does the test light illuminate on either test point of the fuse? If yes, go to next step. If no, go to step  33.
  4. Remove the ignition relay from the underhood bottom junction block using Relay Puller Pliers (J 43244), or equivalent. Probe both test points of the ABS/PCM fuse using a test light connected to a good ground. Does the test light illuminate? If yes, go to step  7. If no, go to next step.
  5. Check the ignition relay load circuit between the ignition relay and the fuses to the circuit components for a short to battery positive voltage. Did you find and correct the condition? If yes, go to step  33. If no, go to next step.
  6. Remove the following fuses from the underhood bottom junction block:
    • Eng Devices
    • Oxy Sen
    • DFI/MDL
    • Trans Sol
    • A/C relay fuse
    • Fuel Inj

    Probe all these fuse terminals in the underhood bottom junction block using a test light connected to a good ground. Does the test light illuminate at any of the fuse terminals? If yes, diagnose engine electrical circuit problem. See ENGINE ELECTRICAL DIAGNOSTIC SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM in appropriate GENERATORS & REGULATORS article. If no, go to step  30.

  7. Disconnect the left Instrument Panel (IP) junction block harness connector that contains the ignition 1 voltage circuit between the left IP junction block and the ignition relay. Check the ignition 1 voltage circuit between the left I/P junction block harness connector and the ignition relay for a short to battery voltage. Did you find and correct the condition? If yes, go to step  33. If no, go to next step.
  8. Check the ignition 1 voltage Buss Bar in the left IP junction block for a short to battery voltage. Did you find a condition? If yes, go to step  32. If no, go to next step.
  9. Disconnect the left IP junction block harness connector that contains the ignition 1 voltage circuit between the ignition switch and the left IP junction block. Check the ignition 1 voltage circuit between the ignition switch and the left IP junction block harness connector for a short to battery voltage. Did you find and correct the condition? If yes, go to step  33. If no, go to next step.
  10. Probe the ignition 1 voltage circuit at the ignition switch harness connector using a test light connected to a good ground. Does the test light illuminate? If yes, go to step  31. If no, go to step  30.
  11. Turn ignition switch to OFF position. Probe both test points of the underhood No. 2, MAXI fuse (60-amp) using a test light connected to a good ground. Does the test light illuminate on both test points of the fuse? If yes, go to step  14. If no, go to next step.
  12. Check the battery positive voltage circuit between the ignition relay and the underhood No. 2, MAXI fuse (60-amp) for a short to ground. Did you find and correct the condition? If yes, go to step  33. If no, go to next step.
  13. Check the relay load circuit between the ignition relay and the fuses to the circuit components for a short to ground. Did you find and correct the condition? If yes, go to step  33. If no, go to step  30.
  14. Turn ignition switch to RUN position, engine OFF. Probe both test point of the ABS/PCM fuse in the left IP junction block using a test light connected to a good ground. Does the test light illuminate on both test points of the fuse? If yes, go to step  20. If no, go to next step.
  15. Does the test light illuminate on one test point of the ABS/PCM fuse? If yes, go to next step. If no, go to step  17.
  16. Turn ignition switch to OFF position. Disconnect the left IP junction block harness connector that contains the ignition 1 voltage circuit between the left IP junction block and the ignition relay. Check the ignition 1 voltage circuit between the ignition relay and the left IP junction block harness connector for a short to ground. Did you find and correct the condition? If yes, go to step  33. If no, go to step  18.
  17. Turn ignition switch to OFF position. Disconnect the left IP junction block harness connector that contains the ignition 1 voltage circuit from the ignition switch. Turn ignition switch to RUN position, engine OFF. Probe the ignition 1 voltage circuit at the left IP junction block harness connector using a test light connected to a good ground. Does the test light illuminate? If yes, go to step  32. If no, go to step  19.
  18. Check the ignition 1 voltage Buss Bar in the left IP junction block for a short to ground. Did you find a condition? If yes, go to step  32. If no, go to step  30.
  19. Turn ignition switch to OFF position. Check the ignition 1 voltage circuit between the ignition switch and the left IP junction block harness connector for an open. Did you find and correct the condition? If yes, go to step  32. If no, go to step  31.
  20. Turn ignition switch to OFF position. Remove the ignition relay using the relay puller pliers. Probe the battery positive voltage circuit of the ignition relay at the underhood bottom junction block using a test light connected to good ground. Does the test light illuminate? If yes, go to next step. If no, go to step  26.
  21. Turn ignition switch to RUN position, engine OFF. Probe the ignition 1 voltage circuit of the ignition relay at the underhood bottom junction block using a test light connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step  25.
  22. Probe the ignition relay coil ground circuit at the underhood bottom junction block using a test light connected to a battery voltage. Does the test light illuminate? If yes, go to next step. If no, go to step  28.
  23. Turn ignition switch to RUN position. Connect a 20-amp fused jumper wire between the battery positive voltage circuit and the ignition relay load circuit at the underhood bottom junction block. Probe the following fuses with at test light connected to a good ground:
    • Eng Devices
    • Oxy Sensor
    • DFI/MDL
    • Trans Sol
    • A/C relay fuse
    • Fuel INJ

    Does the test light illuminate on at least one test point of each fuse? If yes, go to next step. If no, go to step  29.

  24. Check for an intermittent and for a poor connection at the underhood bottom junction block, ignition relay connector location. Did you find and correct the condition? If yes, go to step  33. If no, go to step  30.
  25. Check the ignition 1 voltage Buss Bar circuit in the left IP junction block between the ABS/PCM fuse and the ignition relay for an open. Did you find a condition? If yes, go to step  32. If no, go to step  27.
  26. Repair the high resistance or the open in the battery voltage circuit to the ignition relay. After repair, go to step  33.
  27. Repair the high resistance or the open in the ignition 1 voltage circuit of the ignition relay. After repair, go to step  33.
  28. Repair the high resistance or the open in the ignition relay ground circuit. After repair, go to step  33.
  29. Repair the high resistance or the open in the load circuit of the ignition relay. After repair, go to step  33.
  30. Replace the ignition relay. After repair, go to step  33.
  31. Replace the ignition switch. After repair, go to step  33.
  32. Replace the left instrument panel junction block. After repair, go to step  33.
  33. Replace any open fuses. Turn ignition switch to OFF position for 30 seconds. Did you complete the replacement? If yes, go to next step. If no, go to ENGINE CRANKS BUT DOES NOT RUN under NO-START DIAGNOSTICS in BASIC DIAGNOSTIC PROCEDURES article.
  34. Clear the DTCs using a scan tool. Operate the vehicle for 5 minutes. Does a DTC set during this ignition cycle? If yes, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, system is okay at this time.
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