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Home › Toyota › 2001 › RAV4 Base, AWD, Standard › Repair and Diagnosis › Body & Frame › Body, Cab Control Systems › Body Control Systems › System Tests › Test No. 3: Headlights Do Not Operate But Taillights Operate

Test No. 3: Headlights Do Not Operate But Taillights Operate

  1. Check bulbs for headlights. If bulbs are okay, go to next step. If bulbs are defective, replace bulbs and recheck headlight operation.
  2. Check H-LP LH fuse (10-amp) and H-LP RH fuse (10-amp). Fuses are located in fuse/relay box at driver's side front corner of engine compartment. 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 HEADLIGHT SYSTEMS article or DAYTIME RUNNING LIGHTS article. Passenger's side Junction Block (J/B) Electronic Control Unit (ECU) is located at passenger's side of instrument panel. See Figure.
  3. On models without daytime running lights, go to next step. On models with daytime running lights, go to step  6.
  4. Check headlight relay. See HEADLIGHT RELAY  under COMPONENT TESTS. Headlight relay may also be referred to as H-LP relay. If headlight relay is okay, go to next step. If headlight relay is defective, replace headlight relay and recheck headlight operation.
  5. Check wiring harness and electrical connectors between ground connection and headlight relay, and between headlight relay and passenger's side Junction Block (J/B) Electronic Control Unit (ECU). See WIRING DIAGRAMS in HEADLIGHT SYSTEMS article. Passenger's side J/B ECU is located at passenger's side of instrument panel. See Figure. 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 headlight operation.
  6. Check headlight control switch. See HEADLIGHT CONTROL SWITCH  under COMPONENT TESTS. If headlight control switch is okay, go to next step. If headlight control switch is defective, replace headlight control switch and recheck headlight operation. See HEADLIGHT CONTROL SWITCH  under REMOVAL & INSTALLATION.
  7. Check wiring harness and electrical connectors between headlight control switch and passenger's side Junction Block (J/B) Electronic Control Unit (ECU). See WIRING DIAGRAMS in HEADLIGHT SYSTEMS article or DAYTIME RUNNING LIGHTS article. Passenger's side J/B ECU is located at passenger's side of instrument panel. See Figure. 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 headlight operation.
  8. 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 headlight operation.
  9. Replace passenger's side J/B ECU with a known-good passenger's side J/B ECU and recheck headlight operation. If headlights operate properly, original passenger's side J/B ECU was defective. If headlights still do not operate properly, check wiring harness and electrical connectors for passenger's side J/B ECU, headlights and headlight control switch for intermittent problem. See WIRING DIAGRAMS in HEADLIGHT SYSTEMS article or DAYTIME RUNNING LIGHTS article. Repair wiring harness or electrical connector as necessary.
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