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Test No. 10: All Taillights Do Not Operate

WARNING: This page is about a different car, the 2002 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check TAIL fuse (10-amp) located in driver side junction block under left side of instrument panel. See Figure. If fuse is okay, go to next step. If fuse is defective, repair short in wiring connected to this fuse. See EXTERIOR LIGHTS in SYSTEM WIRING DIAGRAMS article. After repairs, perform confirmation test. See CONFIRMATION TEST .
  2. Check taillight control relay. See TAILLIGHT CONTROL RELAY  under COMPONENT TESTS. If taillight relay is okay, go to next step. If taillight relay is defective, replace taillight relay. After repairs, perform confirmation test. See CONFIRMATION TEST .
  3. Check light control switch. See LIGHT CONTROL SWITCH under COMPONENT TESTS under STEERING COLUMN SWITCHES - AVALON article in ACCESSORIES & EQUIPMENT. If light control switch is okay, go to next step. If light control switch is defective, replace light control switch. After repairs, perform confirmation test. See CONFIRMATION TEST .
  4. Check body control ECU ground circuits. See BODY COMPUTER in SYSTEM WIRING DIAGRAMS article. If ground circuits are faulty, repair and retest system. If ground circuits are okay, substitute original body control ECU with a known-good unit and recheck system operation. If system operates properly, original body control ECU was defective. If system still does not operate properly, perform body control ECU pin voltage check. See BODY CONTROL ELECTRONIC CONTROL UNIT  under PIN VOLTAGE TESTS. Check wiring harness and electrical connectors for an intermittent problem. Repair wiring harnesses or connectors as necessary. If voltage values, harnesses and connectors are okay, replace body control ECU. After repairs, perform confirmation test. See CONFIRMATION TEST . If taillights still do not operate properly, go to next step.
  5. Check wiring harnesses and electrical connectors between battery and taillight control relay, between taillight control relay and body control ECU, between taillight control relay and TAIL (10-amp) fuse, between TAIL (10-amp) fuse and light failure sensor, between body control ECU and light control switch, and between light failure sensor and taillight bulbs. See EXTERIOR LIGHTS in SYSTEM WIRING DIAGRAMS article. Repair wiring harnesses or electrical connectors as necessary. After repairs, perform confirmation test. See CONFIRMATION TEST .
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