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Electrical Load Signal: G20

  1. If using CONSULT-II, go to next step. If not using CONSULT-II, go to step  4.
  2. Turn ignition on. Observe LOAD SIGNAL in DATA MONITOR mode with CONSULT-II. Turn rear window defogger switch to ON position. LOAD SIGNAL should indicate ON. Turn rear window defogger switch to OFF position. LOAD SIGNAL should indicate OFF. If operation is as specified, go to next step. If operation is not as specified, go to step  6.
  3. Turn headlight switch to ON position (2nd position). LOAD SIGNAL should indicate ON. Turn headlight switch to OFF position. LOAD SIGNAL should indicate OFF. If operation is as specified, system is okay. If operation is not as specified, go to step  9.
  4. Turn ignition on. Measure voltage between ground and ECM terminal No. 50 (Red wire) by backprobing. See Figure and Figure . With rear window defogger switch in ON position, battery voltage should exist. With rear window defogger switch in OFF position, zero volts should exist. If voltage is as specified, go to next step. If voltage is not as specified, go to step  6.
  5. Turn headlight switch to ON position (2nd position). Battery voltage should exist. Turn headlight switch to OFF position. Zero volts should exist. If voltage is as specified, system is okay. If voltage is not as specified, go to step  9.
  6. Start engine. Turn rear window defogger switch to ON position. If rear window heats up, go to next step. If rear window does not heat up, repair rear window defogger system. See appropriate REAR WINDOW DEFOGGERS article in ACCESSORIES & EQUIPMENT.
  7. Turn ignition off. Disconnect ECM harness connector. Disconnect rear window defogger relay harness connector located in relay box on right side of engine compartment. Connect negative ohmmeter lead to rear window defogger relay harness connector terminal No. 5 (Blue/Red wire). See Figure. Connect positive ohmmeter lead to ECM harness connector terminal No. 50 (Red wire). Continuity should exist. Reverse ohmmeter leads. Continuity should not exist. If continuity is as specified, go to step  12. If continuity is not as specified, go to next step.
  8. Check the following:
    • Check for poor connection at White, 18-pin in-line harness connector F23 terminal No. 15 (Red wire). See Figure and Figure .
    • Check for poor connection at Super Multiple Junction (SMJ) connector terminal 44K (Blue/Red wire). See Figure. SMJ connector is located under left side of instrument panel, behind fuse block.
    • Check diode at Blue, 4-pin connector M93 located behind top center of instrument panel, taped to main wiring harness. See WIRING DIAGRAMS article.
    • Check diode at White, 6-pin connector M94 located behind top center of instrument panel, taped to main wiring harness. See WIRING DIAGRAMS article.
    • Check for open or short between ECM and rear window defogger relay.

    Repair as necessary.

  9. Start engine. Turn headlight switch to ON position (2nd position). If headlights operate, go to next step. If headlights do not operate, repair headlight system. See appropriate HEADLIGHT SYSTEMS article in ACCESSORIES & EQUIPMENT.
  10. Turn ignition off. Disconnect ECM harness connector. See Figure. Disconnect headlight switch harness connector. Connect positive ohmmeter lead to ECM harness connector terminal No. 50. See Figure. Connect negative ohmmeter lead to headlight switch harness connector terminal No. 9 (Red/Black wire), then terminal No. 10 (Red/Yellow wire). See Fig 1. Continuity should exist. Connect negative ohmmeter lead to ECM harness connector terminal No. 50. Connect positive ohmmeter lead to headlight switch harness connector terminal No. 9 (Red/Black wire), then terminal No. 10 (Red/Yellow wire). Continuity should not exist. If continuity is as specified, go to step  12. If continuity is not as specified, go to next step.
  11. Check the following:
    • Check for poor connection at White, 18-pin in-line harness connector F23 terminal No. 15 (Red wire). See Figure and Figure .
    • Check for poor connection at Super Multiple Junction (SMJ) connector terminals 37K (Red/Yellow wire) and 66K (Red/Black wire). See Figure. SMJ connector is located under left side of instrument panel, behind fuse block.
    • Check diode at White, 6-pin connector M94 located behind top center of instrument panel, taped to main wiring harness. See WIRING DIAGRAMS article.
    • Check for open or short between ECM and headlight switch.

    Repair as necessary.

  12. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
Fig 1: Identifying Headlight Switch Connectors & Terminals (G20)
G00103763Courtesy of NISSAN MOTOR CO., U.S.A.
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