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Headlight Leveling System Acura RL II

Headlights 10 illustrations ~1411 words

Scheme 1

Scheme 1: Component Location Index
Scheme 1: Component Location Index

The headlight leveling system is composed of the headlight leveling control unit, the suspension stroke sensor, and the left and right headlight leveling motors.

The system uses the suspension stroke sensor to monitor the vehicle ride height. The ride height is monitored every 3 minutes while the vehicle is running with the headlight switch ON, and 8 seconds after the vehicles stops with the ignition and headlight switches ON.

If the control unit detects a ride height change, the control unit controls the headlight leveling motors to adjust the headlight vertical position.

Scheme 2

Scheme 2: Headlight Leveling System (With HID)
Scheme 2: Headlight Leveling System (With HID)

Suspension Stroke Sensors

The suspension stroke sensor detects the vehicle posture and send a voltage signal (about 0.4-4.6 V) to the headlight leveling control unit.

Headlight Leveling Control Unit

The headlight leveling control unit is located under the driver's side of the dashboard. The headlight leveling control unit uses the voltage signals it receives from the suspension stroke sensor to determine the voltage signal (about 2-11 V) it sends to control the left and right leveling motors.

Headlight Leveling Motors

The headlight leveling motors are located behind both headlights, and they adjust the headlights vertically based upon the voltage signals (about 2-11 V) they receive from the headlight leveling control unit.

Headlight Initial Position Learning Procedure

Do the headlight initial position learning when any of the related parts of the headlight auto leveling system shown is replaced

  1. Headlight
  2. HID unit
  3. Suspension stroke sensor
  4. Headlight leveling motor
  5. Headlight leveling control unit

Learning Procedure

Before learning the headlights

  1. Park the vehicle on a level surface.
  2. Make sure the tire pressures are correct.

Scheme 3

Scheme 3
Scheme 3
  1. Turn the ignition switch OFF.
  2. Remove all of the baggage from the vehicle.
  3. Slide the front seats backward fully.
  4. Have the driver (about 165 lb (75 kg)) or someone who weighs the same sit in the driver's seat.
  5. Connect the HDS to the data link connector.
  6. Jump the SCS line with the HDS.
  7. Turn the ignition switch ON (II).
  8. Within 5 seconds, turn the headlights (low beam) or passing switch ON and OFF three times repeatedly, and leave them on. If the headlights aiming move down (about 2 in. at 10 feet), then return to the original position, the initial position learning is complete. If the headlights aiming don't move, go to step 1 and repeat the procedure.
  9. Turn the ignition switch OFF, and disconnect the HDS from the data link connector.
  10. Adjust the headlight aim to conform with the applicable requirements.

Scheme 4

Scheme 4: Circuit Diagram
Scheme 4: Circuit Diagram

Scheme 5

Scheme 5: Headlight Leveling Control Unit Input Test
Scheme 5: Headlight Leveling Control Unit Input Test
  1. Turn the ignition switch OFF, remove the driver's dashboard undercover (see «DRIVER'S DASHBOARD UNDERCOVER REMOVAL/INSTALLATION»(/acura/rl/ii-2004-2008/remont/exteriorinterior-trim/#dashboard) ), and the driver's dashboard lower cover (see «DRIVER'S DASHBOARD LOWER COVER REMOVAL/INSTALLATION»(/acura/rl/ii-2004-2008/remont/exteriorinterior-trim/#dashboard) ).
  2. Disconnect the 16P connector (A) from the headlight leveling control unit (B).
  3. Inspect the connector and socket terminals to be sure they are all making good contact. If the terminals are bent, loose or corroded, repair them as necessary, and recheck the system. If the terminals are OK, go to step 4.
  4. With the connector still disconnected, make these input tests at the connector. If any test indicates a problem, find and correct the cause, then recheck the system. If all the input tests prove OK, go to step 5. WIRE CAVITY REFERENCE CHART Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained 15 BLU Ignition switch ON (II), raise the vehicle, make sure it is securely supported, and rotate one of the front wheels slowly with the other wheel blocked. Measure the voltage between the No. 15 (+) and No. 9 (-) terminals: There should be 0-5 V or more and 0-5 V or more repeatedly. Faulty PCM An open in the wire A short to ground in the wire 16 GRN Under all conditions Check for continuity between No. 16 terminal and the combination switch control unit 8P connector No. 2 terminal: There should be continuity. An open in the wire
  5. Reconnect the connector to the control unit, and make these input tests at the connector. If any tests indicates a problem, find and correct the cause, then recheck the system. If all the input tests prove OK, replace the headlight leveling control unit. WIRE CAVITY REFERENCE CHART Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained 1 BLU Ignition switch ON (ID Measure the voltage to ground: There should be battery voltage. Blown No. 29 (7.5A) fuse in the driver's under-dash fuse/relay box An open in the wire 9 BLK Under all conditions Measure the voltage to ground: There should be less than 0.5 V. Poor ground (G401) An open in the wire 4 LT BLU Under all conditions Measure the voltage to ground: There should be less than 0.5 V. Poor ground (G401) An open in the wire 2 YEL Ignition switch ON (ID, headlight ON Measure the voltage between the No. 2 and No. 3 terminals: There should be battery voltage. Faulty headlight leveling motor An open in the wire 3 RED 11 PNK Ignition switch ON (ID, headlight ON Measure the voltage between the No. 11 and No. 3 terminals: There should be about 2 V to 12 V. Faulty headlight leveling motor An open in the wire 3 RED 5 GRY Under all conditions Measure the voltage between the No. 5 (+) arid No. 4 (-) terminals: There should be about 5 V. Measure the voltage between the No. 7 (+) and No. 4 (-) terminals: There should be about 0.5 V to 4.5 V. Faulty suspension stroke sensor An open in the wire 7 PUR 4 LTBLU
  6. After replacing the control unit, do the headlight initial position learning procedure (see «HEADLIGHT INITIAL POSITION LEARNING PROCEDURE»(/acura/rl/ii-2004-2008/remont/headlights/#headlight-leveling-system__headlight-initial-position-learning-procedure) ).

Scheme 6

Scheme 6: Headlight Leveling Motor Input Test
Scheme 6: Headlight Leveling Motor Input Test
  1. Turn the ignition switch OFF.
  2. Disconnect the 3P connector (A) from the headlight leveling motor (B).
  3. Inspect the connector and socket terminals to be sure they are all making good contact. If the terminals are bent, loose or corroded, repair them as necessary, and recheck the system. If the terminals are OK, go to step 4.
  4. Reconnect the connector to the headlight leveling motor, and make these input tests at the connector. If any tests indicate a problem, find and correct the cause, then recheck the system. If all the input tests prove OK, replace the headlight leveling motor (see «HEADLIGHT LEVELING MOTOR REPLACEMENT»(/acura/rl/ii-2004-2008/remont/headlights/#headlight-leveling-system) ). WIRE CAVITY REFERENCE CHART Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained 1 YEL Ignition switch ON (II) Measure the voltage to ground: There should be battery voltage. Faulty headlight leveling control unit An open in the wire 2 PNK Ignition switch ON (II), turn the headlight switch ON Measure the voltage to ground: There should be about 2-12 V. NOTE: Depending on the headlight leveling position. Poor ground (G401) Faulty headlight leveling control unit An open in the wire 3 RED Ignition switch ON (II) Measure the voltage to ground: There should be less than 1 V. Faulty headlight leveling control unit An open in the wire

Scheme 7

Scheme 7: Suspension Stroke Sensor Test
Scheme 7: Suspension Stroke Sensor Test
  1. Remove the suspension stroke sensor (see «SUSPENSION STROKE SENSOR REPLACEMENT»(/acura/rl/ii-2004-2008/remont/headlights/#headlight-leveling-system) ).
  2. Measure the resistance between suspension stroke sensor 3P connector terminals No. 1 and No. 3. There should be about 3.5-6.5 kohms.
  3. Measure the resistance between suspension stroke sensor 3P connector terminals No. 2 and No. 3 with the linkage (A) moved. There should be about 0.5-4.5 kohms.
  4. If the resistance is not as specified, replace the suspension stroke sensor (see «SUSPENSION STROKE SENSOR REPLACEMENT»(/acura/rl/ii-2004-2008/remont/headlights/#headlight-leveling-system) ).

Scheme 8

Scheme 8: Suspension Stroke Sensor Replacement
Scheme 8: Suspension Stroke Sensor Replacement
  1. Lift the vehicle, and support it with safety stands (see «LIFT AND SUPPORT POINTS»(/acura/rl/ii-2004-2008/remont/paintcoatings/#general-information__lift-and-support-points) ).
  2. Disconnect the 3P connector (A) from the suspension stroke sensor (B).
  3. Remove the bolts and nut, then remove the suspension stroke sensor.
  4. Install the sensor in the reverse order of removal.
  5. After replacement, do the headlight initial position learning procedure (see «HEADLIGHT INITIAL POSITION LEARNING PROCEDURE»(/acura/rl/ii-2004-2008/remont/headlights/#headlight-leveling-system__headlight-initial-position-learning-procedure) ).

Scheme 9

Scheme 9: Headlight Leveling Motor Replacement
Scheme 9: Headlight Leveling Motor Replacement

Scheme 10

Scheme 10
Scheme 10
  1. Remove the headlight assembly (see «HEADLIGHT REPLACEMENT»(/acura/rl/ii-2004-2008/remont/exterior-lights/#exterior-lights) ).
  2. Turn the HID light cover 45° counterclockwise to remove it from the headlight housing.
  3. Turn the leveling motor (A) 45° clockwise.
  4. Pull the headlight reflector (A) slightly, and remove the headlight leveling motor (B).
  5. Install in the reverse order of removal.
  6. After installation, do the headlight initial position learning procedure (see «HEADLIGHT INITIAL POSITION LEARNING PROCEDURE»(/acura/rl/ii-2004-2008/remont/headlights/#headlight-leveling-system__headlight-initial-position-learning-procedure) ).