DESCRIPTION
The No. 1 headlight ECU sub-assembly controls the high beam headlights.
WIRING DIAGRAM
for Multiple Beam Headlight
for Single Beam Headlight
CAUTION / NOTICE / HINT
NOTICE:
Click here
Click here
PROCEDURE
1. | CONFIRM MODEL |
(a) Choose the model to be inspected.
Result | Proceed to |
---|---|
for Multiple Beam Headlight | A |
for Single Beam Headlight | B |
B | ![]() | GO TO STEP 3 |
|
2. | PERFORM ACTIVE TEST USING TECHSTREAM |
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / AFS / Active Test.
(e) Perform the Active Test according to the display on the Techstream.
Body Electrical > AFS > Active Test Tester Display | Measurement Item | Control Range | Diagnostic Note |
---|---|---|---|
Headlight High Beam | High beam headlights | OFF or ON | - |
Tester Display |
---|
Headlight High Beam |
OK:
High beam headlights illuminate.
Result | Proceed to |
---|---|
OK | A |
NG (LH side high beam light does not illuminate) | B |
NG (RH side high beam light does not illuminate) | C |
A | ![]() | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
B | ![]() | GO TO STEP 4 |
C | ![]() | GO TO STEP 6 |
3. | PERFORM ACTIVE TEST USING TECHSTREAM |
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / HL AutoLeveling / Active Test.
(e) Perform the Active Test according to the display on the Techstream.
Body Electrical > HL AutoLeveling > Active Test Tester Display | Measurement Item | Control Range | Diagnostic Note |
---|---|---|---|
Headlight High Beam | High beam headlights | OFF or ON | - |
Tester Display |
---|
Headlight High Beam |
OK:
High beam headlights illuminate.
Result | Proceed to |
---|---|
OK | A |
NG (LH side high beam light does not illuminate) | B |
NG (RH side high beam light does not illuminate) | C |
A | ![]() | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
C | ![]() | GO TO STEP 6 |
|
4. | CHECK HEADLIGHT UNIT LH |
(a) Interchange the headlight unit LH with RH and connect the connectors.
Click here
|
5. | CHECK OPERATION (HIGH BEAM HEADLIGHT) |
(a) Check that the high beam headlight operates normally.
OK:
High beam headlight operates normally.
Result | Proceed to |
---|---|
OK | A |
NG (for TMC Made) | B |
NG (for TMMC Made) | C |
A | ![]() | REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY LH |
B | ![]() | REPLACE HEADLIGHT UNIT LH |
C | ![]() | REPLACE HEADLIGHT ASSEMBLY LH |
6. | CHECK HEADLIGHT UNIT RH |
(a) Interchange the headlight unit RH with LH and connect the connectors.
Click here
|
7. | CHECK OPERATION (HIGH BEAM HEADLIGHT) |
(a) Check that the high beam headlight operates normally.
OK:
High beam headlight operates normally.
Result | Proceed to |
---|---|
OK | A |
NG (for TMC Made) | B |
NG (for TMMC Made) | C |
A | ![]() | REPLACE NO. 1 HEADLIGHT ECU SUB-ASSEMBLY RH |
B | ![]() | REPLACE HEADLIGHT UNIT RH |
C | ![]() | REPLACE HEADLIGHT ASSEMBLY RH |
Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Lighting System (w/o Automatic Headlight Beam Level Control System): Headlight Dimmer Switch Circuit
DESCRIPTION The main body ECU (multiplex network body ECU) receives the following switch information:
Light control switch in DRL OFF*, tail, head, AUTO position
Dimmer switch in high, low or high flash (pass) position
*: w/ DRL OFF Switch
WIRING DIAGRAM CAUTION / NOTICE / HINT NOTICE ...
Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual > Air Conditioning System: Back-up Power Source Circuit
DESCRIPTION The back-up power source circuit for the air conditioning amplifier assembly is shown below. Power is supplied even when the engine switch is off. This power is used for diagnostic trouble code memory, etc. WIRING DIAGRAM CAUTION / NOTICE / HINT NOTICE: Inspect the fuses for circuits re ...