Lexus NX: Daytime Running Light Relay Circuit
DESCRIPTION
The illumination of the daytime running light (clearance light assembly) or clearance light is controlled by the headlight ECU sub-assembly.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
PROCEDURE
| 1. | PERFORM ACTIVE TEST USING TECHSTREAM (DAYTIME RUNNING LIGHT) |
(a) Using the Techstream, perform the Active Test.
Click here .gif)
| Tester Display | Measurement Item | Control Range | Diagnostic Note |
|---|---|---|---|
| Clearance Light | Illuminates cornering lights | OFF or ON | - |
| Daytime Running Light | Illuminates daytime running lights | OFF or ON | - |
| Tester Display |
|---|
| Clearance Light |
| Tester Display |
|---|
| Daytime Running Light |
| Result | Proceed to |
|---|---|
| The Active Test is performed normally | A |
| The Active Test is not performed normally for the right side light only | B |
| The Active Test is not performed normally for the left side light only | C |
| A | .gif) | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
| C | | GO TO STEP 5 |
|
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| 2. | CHECK HARNESS AND CONNECTOR (CLEARANCE LIGHT ASSEMBLY RH - BATTERY AND BODY GROUND) |
| (a) Disconnect the clearance light assembly RH connector. |
|
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
|---|---|---|
| A31-3 (DRL) - Body ground | Power switch on (IG) | 11 to 14 V |
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A31-2 (E) - Body ground | Always | Below 1 Ω |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 3. | CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY RH - CLEARANCE LIGHT ASSEMBLY RH) |
(a) Disconnect the A20 headlight ECU sub-assembly RH connector.
(b) Disconnect the A31 clearance light assembly RH connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A20-8 (RLD2) - A31-4 (DRLC) | Always | Below 1 Ω |
| A20-8 (RLD2) or A31-4 (DRLC) - Body ground | Always | 10 kΩ or higher |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 4. | INSPECT CLEARANCE LIGHT ASSEMBLY RH |
(a) Remove the clearance light assembly RH.
for LED Type Side Turn Signal Light:
Click here
for Bulb Type Slide Turn Signal Light:
Click here
(b) Inspect the clearance light assembly RH.
for LED Type Side Turn Signal Light:
Click here
for Bulb Type Slide Turn Signal Light:
Click here
| OK | | REPLACE HEADLIGHT ECU SUB-ASSEMBLY RH |
| NG | | REPLACE CLEARANCE LIGHT ASSEMBLY RH |
| 5. | CHECK HARNESS AND CONNECTOR (CLEARANCE LIGHT ASSEMBLY LH - BATTERY AND BODY GROUND) |
| (a) Disconnect the clearance light assembly LH connector. |
|
(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
| Tester Connection | Switch Condition | Specified Condition |
|---|---|---|
| A30-3 (DRL) - Body ground | Power switch on (IG) | 11 to 14 V |
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A30-2 (E) - Body ground | Always | Below 1 Ω |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 6. | CHECK HARNESS AND CONNECTOR (HEADLIGHT LIGHT CONTROL ECU ASSEMBLY LH - CLEARANCE LIGHT ASSEMBLY LH) |
(a) Disconnect the A19 headlight ECU sub-assembly LH connector.
(b) Disconnect the A30 clearance light assembly LH connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
| Tester Connection | Condition | Specified Condition |
|---|---|---|
| A19-8 (RLD2) - A30-4 (DRLC) | Always | Below 1 Ω |
| A19-8 (RLD2) or A30-4 (DRLC) - Body ground | Always | 10 kΩ or higher |
| NG | | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
| 7. | INSPECT CLEARANCE LIGHT ASSEMBLY LH |
(a) Remove the clearance light assembly LH.
for LED Type Side Turn Signal Light:
Click here
for Bulb Type Slide Turn Signal Light:
Click here
(b) Inspect the clearance light assembly LH.
for LED Type Side Turn Signal Light:
Click here
for Bulb Type Slide Turn Signal Light:
Click here
| OK | | REPLACE HEADLIGHT ECU SUB-ASSEMBLY LH |
| NG | | REPLACE CLEARANCE LIGHT ASSEMBLY LH |
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