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Discussion Starter · #1 ·
Thanks to SilverF16 for this tutorial.
My rear height sensor has corroded due to the winter salt and now my headlights are pointed up at oncoming drivers' face.

Prior to getting it replaced, here's my solution. Thought I share with the group here since a new sensor cost between $100 to $300 (costs I've seen posted) for cars that are no longer under warranty.

Here's a $0 option to get the lights aimed back down and not have to replace the broken sensor. This solution will not give you a malfunction light on your dash either. The one draw back is that you will now disable the Auto leveler system. Which I feel is pretty useless as it is. The auto adjustment under Acceleration and Braking are so minor. Besides all Honda/Acura cars with HID do not have auto leveling system.

Here's what you do:

1. Pull up 5-10 feet away from a wall at night. A dark garage would work here.
2. Turn the ignition to off with headlight off.
3. Turn the ignition to the on position (not start)
4. Now turn on your headlights and watch the headlight adjustment goes thru it range of movements up and down. If you sensor is broke, you will likely see the headlight stop at the highest position (blinding other drivers).
4a. Mark the high and low positions on the wall if necessary. If you choose to do this, you will need a helper to mark the positions.
5. Repeats steps 2-4 to reinitate the headlight movement cycle.
6. As the headlight moves thru it range, and as it gets to the desired point (somewhere between the highest and lowest position), turn off the ignition. You want to turn off the ignition when the headlights are still moving.
6a. By turning off the ignition, you just cutpower to the auto level system and locked the headlight into its new setting.
7. Turn off your headlights.
8. Pull the connector/harness going to the Auto headlight leveling module. This is located on the drivers side above the left kick panel and under the dash. Just crawl under the dash and you will see it. You do not need to remove any trim panels to get to this connector.
8a. The module is labelled auto headlight leveling. It is in a metal casing and has about 20 wires on the connector. It is next to the ABS module and the theft deterent module (if you know where those are). It pretty easy to find if you know where to look for it. See attachment for a guide. It is component labelled H15 in the photo. To remove the connector, you need to first push on the connector tab, the wiggle and pull.
9. You are done. You just locked in your new position and there will be no malfunction light on your dash because you have disabled the entire unit.
10. Go for a drive at night and check your aim. If the aim needs further adjustment, turn off the ignition, turn off your lights, and plug in the connector again. MAKE Sure you turn off ignition and headlight before you plug and unplug the sensor. Now repeats steps 1-8 to readjust.

What about using the manual threaded adjusters on the headlight assembly as an alternative method instead? Well, there is a minor issue with that. On my 2004 model (2002 and earlier may be different), the screwed adjuster are tied in to both the high beam and low beam. So if you tried to lower your low beam headlight so you are not shinning in people face, you will also lower you high beam headlight to the point they are pointed on the ground and will not be effective.

For 2001 and 2002 cars, I believe the vertical adjustment are not coupled so you do have independent adjustment. I don't know how 2003 are setup.

There is a way to de-couple the high and low beam vertical adjustment so you have independent control of both beams, but that can be covered in another thread. I've already de-coupled it so I have independent control.

In addition, you may not want to touch the manual adjustment screws because these are your base factory setting. And why change your base setting to compensate for a failed part. And if you ever do replace the broken sensor, you may have to readjust your base setting again.

Hope this info is useful to some of you.
 

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Headlight leveling solution

Thank you for that post on disconnecting the headlight leveling. I've had the same exact problem: constantly having people flash their highbeams at me, flip me the finger... It screws up my entire driving experience. :lol:

Seriously, I did what you said, and it worked perfectly.
 

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I put a camber kit on my lowered IS and now the auto-adjustment light indicator came on. I followed the steps listed above but when I turn on my headlights the headlight adjustment leveler doesn't go through the motions. The lights just turn straight on (no movements up or down). I tried unplugging the (H15) beam connector (with the ignition off) but that didn't reset the system or anything.
 

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..As I understand it, your suggestion above "tricks", the autoleveling system..

Sorry, but damn, that's stupid. You can, for $5, refurbish your level sensors, I will make a tutorial later.

Here in Denmark, your car will fail the MOT inspection if the autoleveling system doesn't work..
 

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..As I understand it, your suggestion above "tricks", the autoleveling system..
Sorry, but damn, that's stupid. You can, for $5, refurbish your level sensors, I will make a tutorial later.
I looked up your later posts but don't seem to see a tutorial. It would be much appreciated if you could point me to the thread, or if you have the time to create a thread. My headlight levelling indicator has started to come on and the headlights often don't auto-level at the correct position (usually too high). I understand from reading other posts that a common problem is the rear levelling switch develops "issues" (the variable resistor become corroded) and that a new one from Lexus is $300 or so. I might just pull it off myself today and see what can be done, but any tips would be welcome.
 

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..As I understand it, your suggestion above "tricks", the autoleveling system..

Sorry, but damn, that's stupid. You can, for $5, refurbish your level sensors, I will make a tutorial later.
I looked for a later post but I couldn't find one, so I took the repair on myself. I have a 2002 IS300, and the headlight levelling indicator recently started coming on intermittently, and after a few weeks, stayed on all the time. The worst part was that the lights went through their levelling routine when they were turned on, but ended at the highest position. So I was getting flashed ALL the time.

I have a set of the Factory Service Manuals, and after reading through the trouble shooting, and searching on here, I was pretty sure that the problem was a level sensor. With the headlights going through the initial levelling, the headlight adjuster motors were clearly working, but were ending in the wrong spot (they should dip to the bottom, rise to the top, then settle a bit below the top). And the gradual degradation of the problem indicated it was probably a increasing corrosion resistance issue, either in a wiring connection or in one of the level sensors.

The fix was TOO easy. I jacked up the drivers side rear, removed the wheel, and checked the sensor connector. It seemed OK with no sign of corrosion. When I checked the resistance across the sensor pins, they were all "open circuit" (infinite resistance) to each other. The sensor is just a variable resistor, and provides different resistance at various heights. An open circuit wouldn't provide a signal to the headlight control unit.

To remove the sensor, I removed the 10 mm nut on the front of the sensor (that holds the link arm in place, which has a slotted hole to match the sensor shaft) and the two 10 mm bolts that attach the sensor bracket to the frame. I should have taken some photos, but I didn't have my camera handy. Anyway, I placed the sensor on my work bench, and opened it up by removing the four Phillips-headed screws and lifting the tan-coloured top up.
Each of the three connector pins contacts a corresponding point in the top by brass springs. The top has a variable resistor strip embedded into it that a pair of contact arms scribe a semi-circle around. The outer pins have a fixed resistance of about 4k ohms (when they work), and the inner pin and left pin create a resistance of between 1k ohms and 4k ohms, depending on the position of the shaft.

A bit of moisture must have gotten into the sensor, and the one spring was quite corroded, such that it had lost its "spring" and no longer completed the circuit into the top contact. I cleaned out the corroded spring (it fell apart as I pulled it out, while the other springs came out cleanly), cleaned out the socket it sat in, and replaced it with a brass spring from a ball point pen. I also cleaned the resistor track and the other spring beds and contact points with some electrical cleaner, and re-assembled it. There is a rubber O-ring to seal the top to the base, so I cleaned it up and added a bit of plumbers grease to help it seal.

I put in back in place, and tried it out before I installed the link arm. As I rotated the shaft, the headlights went up, and then down when I rotated it the other way.

I haven't confirmed the price of the sensor with Lexus (I will call them next week), but I can't see it worth more than $20 to $30. This is a pretty simple sensor, with just one variable resistor strip, and no other contacts nor function. If they want $300, then it is a rip off.

One thing I noted. If you want the low beam HID headlights to raise a bit without causing the fault indicator to come on, you just need to add ~ 1k ohms of resistance. I have wondered if the HID's could be raised just when the high beams are turned on, since they are actually as bright or brighter than the halogen high beam bulbs and would provide better high beam lighting than the halogens alone. It should be quite easy to splice in a relay that adds 1k ohms to the sensor circuit on high beam, which would be actuated by the high beam circuit. If I get the chance, I'll give it a try and report back.

HTH
 

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Help!!

Okay, I know very little about cars and before I do anything on them, I like to make sure I know what I am doing. I'm trying to do this DIY and I'm having some trouble finding the harness where the auto-leveling headlight connects to. Can anyone point it out in the pictures I have posted? Thanks for the help.

Here are the pics:
sqchess/levelor - Photobucket - Video and Image Hosting
 

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Beam problem

Hey guys, I couldn't seem to find any info on my problem, so I'm gonna ask here. I just replaced my H.I.D bulbs with new aftermarket ones(Philips). First off, they no longer level themselves when turning the ignition, and now the beam is all over the place...there is no straight beam when aiming at the wall. Hopefully this can be resolved..
 

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the headlight levelling indicator recently started coming on intermittently, and after a few weeks, stayed on all the time.

To remove the sensor, I removed the 10 mm nut on the front of the sensor (that holds the link arm in place, which has a slotted hole to match the sensor shaft) and the two 10 mm bolts that attach the sensor bracket to the frame. I should have taken some photos

A bit of moisture must have gotten into the sensor, and the one spring was quite corroded, such that it had lost its "spring" and no longer completed the circuit into the top contact.
I had exactly the same problem. Have checked the rear sensor and it was sparkling clean. Taken the front one out and bingo. (see the pictures)

I've cleaned everything, put new springs in, drove around... and the warning light is still on. :suspiciou Do I have to reset something somewhere or I'm just out of my luck?
 

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Discussion Starter · #12 ·
You have to reset the ECU to clear codes. Disconnect the battery, hit the brakes a couple times, reconnect.
 

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Okay, I know very little about cars and before I do anything on them, I like to make sure I know what I am doing. I'm trying to do this DIY and I'm having some trouble finding the harness where the auto-leveling headlight connects to. Can anyone point it out in the pictures I have posted? Thanks for the help.

Here are the pics:
sqchess/levelor - Photobucket - Video and Image Hosting
This one
 

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Anyone know the correct length for the rod on the front that attaches the level sensor to the lower control arm on the drivers side? I'm having an issue with my lights bouncing up and down while stopped and they seem to be pointing all the way down otherwise.

Thanks
 

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Wow, this is a very helpful post. Seems that every newbie can fix their Lexus even without going to the Lexus service department.

I got the trouble shooting tips from this site, Lexus repair. so right now I am fixing my car by myself. :)
 

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Front auto-level mounting bracket broke off

I have a question - discovered by accident, was looking for a loud rattle in the front of the car when going over bumps, and found out that the front auto-leveling sensor is dangling on the connector wire. apparently the sensor mounting bracket broke off the chassis.

Do you guys think its worth welding it back on? I have doubts about corrosion on the weld spots. Or simply disconnect the leveling mechanism as described?


Thanks!
 

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Does anyone know the resistance range of the stock level sensor?
I'm thinking I might try and replace the sensor with a potentiometer mounted under dash to manually electronically adjust the low beams. parts cost for 1 or 2 potentiometers is less then 5$, I'm guessing the range would be close to 0-5k ohms,


I looked for a later post but I couldn't find one, so I took the repair on myself. I have a 2002 IS300, and the headlight levelling indicator recently started coming on intermittently, and after a few weeks, stayed on all the time. The worst part was that the lights went through their levelling routine when they were turned on, but ended at the highest position. So I was getting flashed ALL the time.

I have a set of the Factory Service Manuals, and after reading through the trouble shooting, and searching on here, I was pretty sure that the problem was a level sensor. With the headlights going through the initial levelling, the headlight adjuster motors were clearly working, but were ending in the wrong spot (they should dip to the bottom, rise to the top, then settle a bit below the top). And the gradual degradation of the problem indicated it was probably a increasing corrosion resistance issue, either in a wiring connection or in one of the level sensors.

The fix was TOO easy. I jacked up the drivers side rear, removed the wheel, and checked the sensor connector. It seemed OK with no sign of corrosion. When I checked the resistance across the sensor pins, they were all "open circuit" (infinite resistance) to each other. The sensor is just a variable resistor, and provides different resistance at various heights. An open circuit wouldn't provide a signal to the headlight control unit.

To remove the sensor, I removed the 10 mm nut on the front of the sensor (that holds the link arm in place, which has a slotted hole to match the sensor shaft) and the two 10 mm bolts that attach the sensor bracket to the frame. I should have taken some photos, but I didn't have my camera handy. Anyway, I placed the sensor on my work bench, and opened it up by removing the four Phillips-headed screws and lifting the tan-coloured top up.
Each of the three connector pins contacts a corresponding point in the top by brass springs. The top has a variable resistor strip embedded into it that a pair of contact arms scribe a semi-circle around. The outer pins have a fixed resistance of about 4k ohms (when they work), and the inner pin and left pin create a resistance of between 1k ohms and 4k ohms, depending on the position of the shaft.

A bit of moisture must have gotten into the sensor, and the one spring was quite corroded, such that it had lost its "spring" and no longer completed the circuit into the top contact. I cleaned out the corroded spring (it fell apart as I pulled it out, while the other springs came out cleanly), cleaned out the socket it sat in, and replaced it with a brass spring from a ball point pen. I also cleaned the resistor track and the other spring beds and contact points with some electrical cleaner, and re-assembled it. There is a rubber O-ring to seal the top to the base, so I cleaned it up and added a bit of plumbers grease to help it seal.

I put in back in place, and tried it out before I installed the link arm. As I rotated the shaft, the headlights went up, and then down when I rotated it the other way.

I haven't confirmed the price of the sensor with Lexus (I will call them next week), but I can't see it worth more than $20 to $30. This is a pretty simple sensor, with just one variable resistor strip, and no other contacts nor function. If they want $300, then it is a rip off.

One thing I noted. If you want the low beam HID headlights to raise a bit without causing the fault indicator to come on, you just need to add ~ 1k ohms of resistance. I have wondered if the HID's could be raised just when the high beams are turned on, since they are actually as bright or brighter than the halogen high beam bulbs and would provide better high beam lighting than the halogens alone. It should be quite easy to splice in a relay that adds 1k ohms to the sensor circuit on high beam, which would be actuated by the high beam circuit. If I get the chance, I'll give it a try and report back.

HTH
 

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Definitely will have to try this, just buffed out the headlights on my is300 (Headlights were looking rough from previous owner, just bought the car a couple days ago) and the headlight leveler imbalance dash light came on and I definitely don't wanna spend money to fix this when I could be modding!
 

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@ Longnights

You're such a lifesaver. I just purchased a 2004 IS300 and I noticed the leveling light was out. I check the sensors and apparently, the rear sensor's metal housing snapped and it was dangling by wires, one of which also snapped. As replacement for the whole mounting was the only option, pulling the autoleveling connection was perfect.
 
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