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Headlight Leveling System Acura MDX II

Headlights 18 illustrations ~1981 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 left-front and left-rear suspension stroke sensors, and the left and right headlight leveling motors.

The system uses the left-front and left-rear suspension stroke sensors 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
Scheme 2: Headlight Leveling System

Suspension Stroke Sensors

The suspension stroke sensors are also one of the active damper system components. The headlight leveling system uses the left-front and left-rear suspension stroke sensor signals. The left-front suspension stroke sensor is located at the left front suspension area. A short link connects the arm of the sensor to the stabilizer bar. The left-rear suspension stroke sensor is located at the left rear suspension area. A short link connects the arm of the sensor to the damper assembly.

The sensors detect the vehicle ride height and sends 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 passenger's side of the dashboard. The headlight leveling control unit uses the voltage signals it receives from the left-front and left-rear suspension stroke sensors 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.

Scheme 3

Scheme 3: Circuit Diagram
Scheme 3: Circuit Diagram

Suspension Stroke Sensor Circuit Troubleshooting

Note. Before troubleshooting, check the No. 31 (15 A) fuse in the under-dash fuse/relay box. Check the active damper system for DTCs and troubleshoot those codes first.

Scheme 4

Scheme 4: Suspension Stroke Sensor Circuit Troubleshooting
Scheme 4: Suspension Stroke Sensor Circuit Troubleshooting

Scheme 5

Scheme 5
Scheme 5

Scheme 6

Scheme 6
Scheme 6

Scheme 7

Scheme 7
Scheme 7

Scheme 8

Scheme 8
Scheme 8

Scheme 9

Scheme 9
Scheme 9

Scheme 10

Scheme 10
Scheme 10

Scheme 11

Scheme 11
Scheme 11
  1. Raise the vehicle, make sure it is securely supported.
  2. Disconnect the 3P connector (A) from the left-front stroke sensor (B).
  3. Disconnect the 3P connector (A) from the left-rear stroke sensor (B).
  4. Turn the ignition switch to ON (II).
  5. Turn the combination light (headlight) switch ON.
  6. Check for continuity between the left-front and left-rear suspension stroke sensors 3P connector No. 3 terminal and body ground individually. Is there continuity? YES - Go to step 7. NO - Repair open in the wire or poor ground (G401), if the wire is OK, replace the headlight leveling control unit.
  7. Measure the voltage between the left-front and left-rear suspension stroke sensor 3P connector No. 1 terminal and body ground individually. Is there about 5 V? YES - Go to step 8. NO - Check for an open or a short in the wire between the headlight leveling control unit and the left-front (or left-rear) suspension stroke sensor. If the wire is OK, replace the left-front (or left-rear) suspension stroke sensor.
  8. Remove the nut (A) and the left-front suspension stroke sensor from the suspension side.
  9. Remove the nut (A) and the left-rear suspension stroke sensor from the suspension side.
  10. Reconnect the 3P connector to each suspension stroke sensor.
  11. Measure the voltage between the headlight leveling control unit 16P connector No. 4 and No. 7 terminals, and No. 6 and No. 12 terminals while the suspension stroke sensor arm (A) is moved. Is there about 0.5-4.5 V? YES - Intermittent failure, the system is OK at this time. Check for loose or poor connections between the headlight leveling control unit and the left-front (or left-rear) suspension stroke sensor, if the connections are OK, replace the left-front (or left-rear) suspension stroke sensor. NO - Check for an open or a short in the wire between the headlight leveling control unit and the left-front (or left-rear) suspension stroke sensor, if the wire is OK, replace the left-front (or left-rear) suspension stroke sensor.

Scheme 12

Scheme 12: Headlight Leveling Control Unit Input Test
Scheme 12: Headlight Leveling Control Unit Input Test
  1. Turn the ignition switch to LOCK (0), and remove the glove box (see «GLOVE BOX REMOVAL/INSTALLATION»(/acura/mdx/ii-2006-2010/remont/exteriorinterior-trim/#dashboard__glove-box-removalinstallation) ).
  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. CAVITY AND TEST CONDITION 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 LT BLU Under all conditions Check for continuity between the No. 16 terminal and the Non terminal of the combination switch control unit 8P connector: There should be continuity. An open in the wire
  5. Reconnect the connector, turn the ignition switch to ON (II), and make these input tests at the connector. If any test indicate a problem, find and correct the cause, then recheck the system. If all the input tests prove OK, replace the headlight leveling control unit. NOTE: After replacing the control unit, do the headlight initial position learning procedure (see «HEADLIGHT INITIAL POSITION LEARNING PROCEDURE»(/acura/mdx/ii-2006-2010/remont/headlights/#headlight-leveling-system__headlight-initial-position-learning-procedure) ). CAVITY AND TEST CONDITION CHART Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained 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 3 GRN 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 GRN 12 BLU 8 RED Under all conditions Measure the voltage to ground: There should be battery voltage. Blown No. 3 (10 A) fuse in the main under-hood fuse box A short to ground in the wire 1 RED Ignition switch ON (II) Measure the voltage to ground: There should be battery voltage. Blown No. 31 (15 A) fuse in the under-dash fuse/relay box An open in the wire 2 BLU Ignition switch ON (II), headlight switch 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 GRN 11 BRN Ignition switch ON (II), headlight switch ON Measure the voltage between the No. 11 and No. 3 terminals: There should be about 2 to 12 V. Faulty headlight leveling motor An open in the wire 3 GRN 6 PUR Under all conditions Measure the voltage between the No. 13 and No. 12 terminals: There should be about 5 V. Measure the voltage between the No. 6 and No. 12 terminals: There should be about 0.5 to 4.5 V. Faulty left-front suspension stroke sensor An open in the wire 12 BLU 13 PNK 4 LT GRN Under all conditions Measure the voltage between the No. 5 and 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 to 4.5 V. Faulty left-rear suspension stroke sensor An open in the wire 5 RED 7 LT BLU

Scheme 13

Scheme 13: Headlight Leveling Motor Input Test
Scheme 13: Headlight Leveling Motor Input Test
  1. Turn the ignition switch to LOCK (0).
  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/mdx/ii-2006-2010/remont/headlights/#headlight-leveling-system) ). CAVITY AND TEST CONDITION CHART Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained 1 BRN Ignition switch ON (II) Measure the voltage to ground: There should be about 2-12 V. NOTE: Depending on the headlight leveling position. Faulty headlight leveling control unit An open in the wire 2 GRN 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 3 BLU Ignition switch ON (II) Measure the voltage to ground: There should be battery voltage. Faulty headlight leveling control unit An open in the wire

Suspension Stroke Sensor Replacement

Note. Right side of suspension stroke sensor for active damper system is the same procedure as left side suspension stroke sensor. After install the rear suspension stroke sensor, do the memorizing rear suspension full rebound position (see MEMORIZING REAR SUSPENSION FULL REBOUND POSITION ).

Scheme 14

Scheme 14: Suspension Stroke Sensor Replacement
Scheme 14: Suspension Stroke Sensor Replacement

Scheme 15

Scheme 15
Scheme 15
  1. Raise the vehicle, make sure it is securely supported.
  2. Disconnect the 3P connector (A) from the suspension stroke sensor (B). LEFT-FRONT LEFT-REAR
  3. Remove the bolt and nut, then remove the suspension stroke sensor.
  4. Install the sensor in the reverse order of removal.
  5. After installing, do the headlight initial position learning procedure (see «HEADLIGHT INITIAL POSITION LEARNING PROCEDURE»(/acura/mdx/ii-2006-2010/remont/headlights/#headlight-leveling-system__headlight-initial-position-learning-procedure) ).

Scheme 16

Scheme 16: Removal
Scheme 16: Removal
  1. Remove the headlight assembly (see «HEADLIGHT REPLACEMENT»(/acura/mdx/ii-2006-2010/remont/exterior-lights/#exterior-lights) ).
  2. Turn the headlight leveling motor (A) 45° counterclockwise.
  3. Turn the adjuster (B) of the headlight leveling motor until the headlight leveling motor shaft (C) is removed from the headlight.

Scheme 17

Scheme 17: Installation
Scheme 17: Installation
  1. Insert the headlight leveling motor shaft (A) into the headlight housing, then turn the adjuster (B) until the shaft connects to the headlight.
  2. Turn the headlight leveling motor (C) 45° clockwise to install to the headlight.
  3. Tighten the adjuster until fully it is secure, but do not over tighten, then back it off 9 turns.
  4. Insert the headlight in the reverse order of removal.
  5. After installing, do the headlight leveling motor initial position learning procedure (see «HEADLIGHT INITIAL POSITION LEARNING PROCEDURE»(/acura/mdx/ii-2006-2010/remont/headlights/#headlight-leveling-system__headlight-initial-position-learning-procedure) )

Headlight Initial Position Learning Procedure

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

  1. Headlight
  2. HID unit
  3. Left-front suspension stroke sensor
  4. Left-rear suspension stroke sensor
  5. Headlight leveling motor
  6. 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 18

Scheme 18
Scheme 18
  1. Turn the ignition switch to LOCK (0).
  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 moves down (about 2 in. at 10 feet), then returns to the original position, the initial position learning is complete. If the headlights aiming doesn't move, go to step 1 and repeat the procedure.
  9. Turn the ignition switch to LOCK (0), and disconnect the HDS from the data link connector.
  10. Adjust the headlight aim to conform with the applicable requirements.