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Test D: Generator Noise Diagnosis

  1. Test generator for proper operation. See TEST A: CHARGING SYSTEM TEST  . If generator is operating properly, go to next step. If generator is not operating properly, go to step  11 .
  2. Start engine. Verify that generator noise can be heard. Turn switch to OFF position. Disconnect generator 4-pin harness connector. Start engine. Listen for generator noise. If noise does not exist, go to step  11 . If noise still exist, go to next step.
  3. Turn switch to OFF position. Remove drive belt. Spin generator pulley by hand. If pulley rotates smoothly and noise does not exist, go to next step. If pulley rotates roughly and/or noise exists, go to step  11 .
  4. Inspect pulley for looseness, or loose pulley nut. If pulley and nut are okay, go to next step. If pulley and/or nut is loose, go to step  11 .
  5. Loosen all generator mounting bolts. Tighten all mounting bolts to specification. See TORQUE SPECIFICATIONS  . Install drive belt. Start engine and listen for noise. If noise has decreased or stopped, system is okay. If noise still exists, go to next step.
  6. Check for stretched generator connections, or hoses or other equipment rubbing on generator. If problem exists, repair as necessary. After repair, go to next step. If problem does not exist, go to step  8 .
  7. Reroute electrical connections, hoses, etc., away from generator. Start engine and listen for noises. If noise has decreased or stopped, system is okay. If noise still exists, go to next step.
  8. Check drive belt for proper tension. If drive belt is loose, go to next step. If drive belt is okay, go to step  10 .
  9. Replace drive belt tensioner. Start engine and listen for noise. If noise has decreased or stopped, system is okay. If noise still exists, go to step  11 .
  10. Check comparable vehicle for similar noise. If noise exists in similar vehicle, system is okay. If noise does not exist in similar vehicle, go to next step.
  11. If no definite generator problems were found, ensure all other possible sources of noise are eliminated. If all possibilities have been eliminated, replace generator. See GENERATOR  under REMOVAL & INSTALLATION. After repair, go to next step.
  12. Start engine and verify that noise is reduced or eliminated. If noise is still objectionable, go to step  2 .
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