i have a 2003 z with a headlight that would or wouldn't open on occasion,last time it wouldn't open I messed with the **** on top of motor and got it to the point it started to lift the cover and backed off a bit and all seemed good, it happened again a couple weeks later and I did the same and it opened fine but now when it closes it grinds as motor doesn't shut off for about 3 seconds but sounds awful. motor seems to have plenty of power but don't know how to adjust, ideas? tks in advance,

 

It seems you probably have a broken plastic gear.

Get a kit like this one (pay attention because there are 2 different kits: one for "97 to early 2000" and another for "late 2000 to 2004") and follow these step-by-step directions. You'll save money and they will last forever.

It would be wise to replace as well the rubber bump stops in both sides. You can get them here.

There is a TSB, that calls for shimming the driver's side motor. The parts needed for this are included in the above mentioned kit (#2 in diagram below).

 

you are more than likely correct but why if it is my gear does it open and close fine but when closes it seems to continue running for a few extra seconds,

 

Because the plastic gear probably has a few missing/damaged teeth in the area that corresponds to the "closed" position. The noise that you are hearing is the metal worm gear in the motor grinding against the damaged plastic gear .

The way the headlights work is not based on predetermined positions. When the headlight doors open or close and they reach the end of their travel, they press against the corresponding rubber bump stops. As a result, the current through the headlight motors increases and that is sensed by the Headlight Door Control Module, which in turn cuts power to the motors.

The missing/damaged teeth are causing a faulty gear-to-worm engagement at the end of the closing travel. As a consequence, when the door closes, even though the bump stop is contacted, the worm keeps spinning almost freely against the plastic gear. This causes the motor to continue to run because its current is not reaching fast enough the needed level for the HDCM to cut the power.

​​​​

 

There are no limit switches built in to the motor; IIRC, the controller looks at current to determine when the gears should stop turning (peak current at motor stall means it's done.)

So it keeps running for a second because due to the (likely) ground off plastic teeth, it doesn't hit that stall.

 

Not a new motor but a new "brass" gear. Take a look at the kit at Rodney Dickman dot com
P.S. The kit is complete ...step by step with pic's. and grease and the T brace and brass gear.

 

Take a look at Post 2 for direct links.

 

I fixed mine by just turning the gear in the motor 180 degrees and flipping the bump stops--Costs --0. Here are the instructions I sent another member.

Hey Denny-Sorry for the late reply. First raise the headlights and back off one turn on the control to leave them up but turns the lights off. Then all you have to do is remove the black shroud around the headlight, and I removed the top (painted part) of it as well for some additional room. Note the position of those screws so you can install it the same way. Then remove the nut on the motor arm and gently pry off the arm with a small pry bar. Make sure you hold the headlight up when doing so as it will now fall down if you don't. I used a bunched up thick towel to hold it up while working on it. Notice the position on the flat part of the arm on the motor--and after removing the motor cover just manually turn the arm 180 deg( will take quite a few turns of the **** and go slow when you get to the stopping point) and then re-attach the arm. The plastic gear inside is now operating on a new part of the gear. Check the bump stops for wear--I just went ahead and turned them over while I was in there due to obvious wear (actual grooves worn down to the metal) so all new parts were being used. Be sure to hold on to the stops because one of mine popped off and it took me an additional 30 mins to find it. Just put everything back as it was and test the operation. Should work as new.