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Test No. 14: Automatic Turn Off System For Lighting System Does Not Operate

NOTE: Automatic turn off system turns off the lights when driver's side front door is opened with the ignition off and headlights are turned on.
  1. Check that retaining screw on door courtesy switch for driver's side front door is tight to provide good ground connection. Door courtesy is located on pillar post at rear of driver's side front 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 automatic turn off system operation. If automatic turn off system still does not operate, go to next step. If automatic turn off system operates, the problem was the loose retaining screw on door courtesy switch.
  2. 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 automatic turn off system operation.
  3. Check wiring harness and electrical connectors between door courtesy switch for driver's side front door and body Electronic Control Unit (ECU). See WIRING DIAGRAMS in POWER DOOR LOCKS & REMOTE KEYLESS ENTRY SYSTEMS - PRIUS article. Body ECU is located at driver's side of instrument panel on the fuse/relay box and contains an 18-pin and 20-pin electrical connector. See Figure. 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 automatic turn off system operation.
  4. Check body ECU for proper voltage and input signals. See BODY 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 automatic turn off system operation.
  5. Replace body ECU with a known-good body ECU and recheck automatic turn off system operation. If automatic turn off system operates properly, original body ECU was defective. If automatic turn off system still does not operate properly, check wiring harness and electrical connectors between door courtesy switch for driver's side front door and body ECU for intermittent problem. See WIRING DIAGRAMS in POWER DOOR LOCKS & REMOTE KEYLESS ENTRY SYSTEMS - PRIUS article. Repair wiring harness or electrical connector as necessary.
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