Lexus ES: Taillight Relay Circuit
DESCRIPTION
The main body ECU (multiplex network body ECU) controls the operation of the TAIL relay.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
- Inspect the fuses for circuits related to this system before performing the following procedure.
-
Before replacing the main body ECU (multiplex network body ECU), refer to Registration.
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PROCEDURE
| 1. | PERFORM ACTIVE TEST USING TECHSTREAM |
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / Main Body / Active Test.
(e) Perform the Active Test according to the display on the Techstream.
Body Electrical > Main Body > Active Test| Tester Display | Measurement Item | Control Range | Diagnostic Note |
|---|---|---|---|
| Taillight Relay | Taillight relay | OFF or ON | - |
| Tester Display |
|---|
| Taillight Relay |
OK:
Taillights illuminate.
| OK | .gif) | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
|
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| 2. | CHECK HARNESS AND CONNECTOR (POWER SOURCE - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY) |
(a) Disconnect the 3K instrument panel junction block assembly connector.
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| 3K-1 - Body ground | Power switch off | 11 to 14 V |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 3. | INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY |
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| *a | Component without harness connected (Instrument Panel Junction Block Assembly) | - | - |
(a) Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.
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(b) Connect a positive (+) lead from the auxiliary battery to terminal 3K-1.
(c) Connect a negative (-) lead from the auxiliary battery to terminal MB-14 (TRLY).
(d) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| 3H-30 - Auxiliary battery negative (-) terminal | Always | 11 to 14 V |
| OK | | REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) |
| NG | | REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY |
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High Beam Headlight Circuit
DESCRIPTION The headlight ECU sub-assembly controls the high beam headlights. WIRING DIAGRAM except Bulb Type Turn Signal Light (for TMMK Made) for Bulb Type Turn Signal Light (for TMMK Made) CAUTIO
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Headlight Dimmer Switch Circuit
DESCRIPTION The steering sensor receives the following switch information:
Light control switch in DRL OFF*1, off*2, tail, head or AUTO position
Dimmer switch in high, low or high flash (pass) position
*1: w/ DRL OFF Switch
*2: w/o DRL OFF Switch
WIRING DIAGRAM CAUTION / NOTICE / HI
Inspection
INSPECTION PROCEDURE 1. INSPECT TURN SIGNAL SWITCH (a) Measure the resistance according to the value(s) in the table below. Standard Resistance: Light Control Switch Tester Connection Condition Specified Condition
*1: w/ Light Control Switch DRL OFF Position
2 (L_OFF) - 12 (EL)
