I decided to put this together after seeing the question My left/right headlight makes a terrible noise for about five seconds after it lowers... whatís wrong? asked several times. So, if it sounds like the entire front end of your car is about to explode for a few seconds when you turn your lights off, read on and possibly save yourself some $$$ :) If youíve had your car to the dealer for this problem, they probably told you the headlight motor was bad and you needed a new one. Then, when they gave you the price, your mouth fell to the floor and you turned around and walked out.
These little motors are not cheap. I believe they cost around $200 EACH! What the dealers donít know (or maybe donít want you to know :) is there is a very easy FREE fix for this problem that works 9 out of 10 times. You see, nothing is actually wrong with the motor itself... the problem is a plastic gear inside of the housing has stripped. The really good news is that only half of this plastic gear is being used! Yep, full travel of the headlight from down to up then down again uses exactly 1/2 of the plastic gear because the motor shaft only turns 180 degrees to raise the headlight then turns the opposite direction (180 degrees again) to lower the light. There is a very easy process that enables you to use the other side of the gear.
1. Start with the headlight in the down position. Remove the plastic (or sometimes rubber) cover over the headlight motor assembly and use the Manual Raise/Lower knob to raise the headlight to the full up position.
2. With the headlight fully raised, remove the four screws holding the plastic trim piece that goes around the headlight. This is being removed to provide for easier access later on. Two of them can be seen in the picture to the left. The other two are on the opposite side.
3. Now that the trim piece has been removed, access to the headlight motor shaft end nut will be easier. The next step is to remove the motor shaft nut so that the headlight raise/lower arm can be pulled away from the motor shaft. For now, only remove the nut.
4. With the nut removed, pull the raise/lower arm off the motor shaft. Note: This will be easier if you have somebody to help you hold the headlight up because it will not stay up by itself once this arm is pulled off the shaft :) Youíll notice that the shaft is not perfectly round. It has two flat spots. You need to look at how these flat spots on the shaft are situated... one of the flat areas should be approx. facing the front of the car and the other towards the rear.
5. This next part is important! You now need to, while CLOSELY watching the motor shaft, rotate the raise/lower manual knob so the motor shaft turns exactly 180 degrees (or half a revolution). Once you have completed this, reattach the headlight raise lower arm. What you have just done is made it so the actual motor gear will now be in contact with the *other* half of the plastic gear. Sure, the teeth on the plastic gear are stripped, but they are stripped on the now unused side of the gear :) Reattach the motor shaft nut and manually lower the headlight with the manual raise/lower knob... do NOT go too far! Stop lowering once the headlight gets about flush with the hood. It will automatically align itself properly once it has been electrically raised then lowered. Put everything together and you should now have a quiet headlight!
You could take everything apart, lift up the plastic gear, rotate it 180 degrees, then reinsert the plastic gear to fix the problem. BUT, I do believe the above method is just a little bit easier. If, for some reason the above method failed, you could remove the cover on the gear housing and try to manually position the plastic gear so only good teeth are being used. Use epoxy to reattach the cover.
Yeah, this would be a bit of work but as a last ditch effort, itís worth a shot! In this picture if you look closely you can see where a portion of the plastic gear teeth are actually worn away in the center. This is what causes the ratcheting and vibrating effect when the headlight reaches the closed position and in some cases, the fully raised position.
What happens is the motor continues to turn (even though the plastic gear is not) and therefore the sensing circuit still thinks the headlight is moving in the up or down direction. Well, thatís it! I bet you didnít think I could go into so much detail with a simple headlight motor, huh?
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