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Test No. 9: Headlight On Warning System Does Not Operate

NOTE: Headlight on warning system will sound a buzzer if headlights are on and driver's side front door is opened and ignition key is removed from the ignition.
  1. Note location of passenger's side Junction Block (J/B) Electronic Control Unit (ECU) at passenger's side of instrument panel, electrical connectors and terminal identification. See Figure.
  2. Turn ignition on. Using voltmeter, check voltage between passenger's side J/B ECU electrical connector 3C terminal No. 9 and electrical connector 3G terminal No. 7 at passenger's side J/B ECU. See Figure. Also, check voltage between passenger's side J/B ECU electrical connector 3C terminal No. 9 and electrical connector 3Q terminal No. 6 at passenger's side J/B ECU. See Figure. Voltage should be 10-14 volts. If voltage is not within specification, turn ignition off. Go to next step. If voltage is within specification, turn ignition off. Go to step  7.
  3. Check ACC fuse (7.5-amp), AMI fuse (40-amp) and GAUGE fuse (10-amp). Fuses are located in fuse/relay box at driver's side of instrument panel. See Figure. If fuses are okay, go to next step. If any fuse is defective, repair short in wiring for appropriate fuse. See WIRING DIAGRAMS in ILLUMINATION/INTERIOR LIGHTS article. For additional wiring for power supply circuit, see POWER DISTRIBUTION article in WIRING DIAGRAMS.
  4. Check ignition switch. See IGNITION SWITCH  under COMPONENT TESTS. If ignition switch is okay, go to next step. If ignition switch is defective, replace ignition switch and recheck operation of headlight on warning system. See IGNITION SWITCH  under REMOVAL & INSTALLATION.
  5. Check wiring harness and electrical connectors between GND1, GND2 terminals on passenger's side J/B ECU and ground connection. See WIRING DIAGRAMS in ILLUMINATION/INTERIOR LIGHTS article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary and recheck operation of headlight on warning system.
  6. Check wiring harness and electrical connectors between battery and passenger's side J/B ECU. See WIRING DIAGRAMS . For additional power supply, see POWER DISTRIBUTION article in WIRING DIAGRAMS. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector is defective, repair as necessary and recheck operation of headlight on warning system.
  7. Check that retaining screw on door courtesy switch at driver's side front door is tight to provide good ground connection. Door courtesy is located on pillar post at rear of door. See Figure. If retaining screw for door courtesy switch is tight and good ground connection exists, go to next step. If retaining screw for door courtesy switch is loose, tighten retaining screw and recheck operation of headlight on warning system. If headlight on warning system still does not operate, go to next step. If headlight on warning system operates, the problem was the loose retaining screw on door courtesy switch.
  8. Check door courtesy switch for driver's side front door. See DOOR COURTESY SWITCH  under COMPONENT TESTS. If door courtesy switch is okay, go to next step. If door courtesy switch is defective, replace door courtesy switch and recheck operation of headlight on warning system.
  9. Check wiring harness and electrical connectors between door courtesy switch for driver's side front door and passenger's side J/B ECU. See WIRING DIAGRAMS in KEYLESS ENTRY SYSTEMS - RAV4 article. If wiring harness and electrical connectors are okay, go to next step. If wiring harness or electrical connector are defective, repair as necessary and recheck operation of headlight on warning system.
  10. Check printed circuit board in combination meter on instrument cluster for problem which prevents operation of buzzer for headlight on warning system. Wiring circuit for buzzer for headlight on warning system goes into combination meter. See WIRING DIAGRAMS in WARNING SYSTEMS article. For identification of combination meter electrical connectors, see Figure. If printed circuit board is okay, go to next step. If printed circuit board is defective, repair or replace components and recheck operation of headlight on warning system.
  11. Check passenger's side J/B ECU for proper voltage and input signals. See PASSENGER'S SIDE JUNCTION BLOCK ELECTRONIC CONTROL UNIT  under PIN VOLTAGE TESTS. If proper voltage and input signals exist, go to next step. If proper voltage and input signals do not exist, repair as necessary and recheck operation of headlight on warning system.
  12. Replace passenger's side J/B ECU with a known-good passenger's side J/B ECU and recheck operation of headlight on warning system. If headlight on warning system operates properly, original passenger's side J/B ECU was defective. If headlight on warning system still does not operate properly, check wiring harness and electrical connectors for passenger's side J/B ECU and headlight on warning system for intermittent problem. See WIRING DIAGRAMS in WARNING SYSTEMS article. Repair wiring harness or electrical connector as necessary.
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