Inspection Procedure
WARNING: This page is about a different car, the 2002 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
For circuit wiring diagram, see Fig 1.
- Check that the taillight and the headlight light up. If the lights light up, go to the next step. If the lights do not light up, see TEST A: HEADLIGHT (LO BEAM, DISCHARGE) DOES NOT LIGHT UP or TEST B: TAILLIGHT DOES NOT LIGHT UP .
- Read the value of the hand-held tester. Connect the hand-held tester to the DLC3. Turn the ignition switch ON and push the hand-held tester main SW ON. Select the item AUTO LIGHT SW in the DATA LIST and read it's value displayed on the hand-held tester. If the light control SW AUTO turns ON, go to the next step. If the light control SW except AUTO turns OFF, replace the headlight dimmer switch. See HEADLAMP DIMMER/TURN SIGNAL SWITCH ASSEMBLY under REMOVAL & INSTALLATION in STEERING COLUMN SWITCHES - ES 300 article.
- Check the automatic light control sensor. Check the continuity between terminal No. 3 (+) and body ground. See CONNECTOR IDENTIFICATION . See AUTOMATIC LIGHT CONTROL SENSOR CONDITION table. Measure the voltage between terminals. Using an oscilloscope, check the signal waveform appears between terminals. If the results are OK, go to TEST A: HEADLIGHT (LO BEAM, DISCHARGE) DOES NOT LIGHT UP . If the results are not good, go to the next step.AUTOMATIC LIGHT CONTROL SENSOR CONDITION
Terminal No. (Symbol) Tester Connection Condition (Specified Condition) 6 (CLTB) 6 - 3 Constant (10-14 Volts) 3 (CLTE) 3 - Body Ground Constant (Continuity) 5 (CLTS) 5 - 3 IG SW ON Dimmer SW AUTO (Signal Waveform Appears Depending On Outside Brightness) - Check the harness and connector between the driver side junction block assembly and the automatic light control sensor. Check that the signal waveform appears between terminal No. B5-17 (CLTS) and body ground. If a bar appears, check and replace the multiplex network body computer. See MULTIPLEX COMMUNICATION SYSTEMS - ES 300 article in COMMUNICATION DEVICES. If a bar does not appear, go to the next step.
- Check the harness and connector between the driver side junction block assembly automatic light control sensor. Check that the signal waveform appears between terminal No. B5-15 (CLTB) and body ground. If there is 10-14 volts, check and replace the multiplex network body computer. See MULTIPLEX COMMUNICATION SYSTEMS - ES 300 article in COMMUNICATION DEVICES. If there is not 10-14 volts, go to the next step.
- Check the harness and connector between the driver side junction block assembly automatic light control sensor. Check that the signal waveform appears between terminals No. B5-16 (CLTE) of instrument panel junction block and 3 (CLTE) of automatic light control sensor. If there is continuity, check and replace the multiplex network body computer. See MULTIPLEX COMMUNICATION SYSTEMS - ES 300 article in COMMUNICATION DEVICES. If there is not continuity, replace the automatic light control sensor. See INSTRUMENT PANEL SAFETY PAD SUB-ASSEMBLY under REMOVAL & INSTALLATION in INSTRUMENT PANEL - ES 300 article.