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Headlight goes up half issue

12 March 2020
Hello everyone!
first post and sadly it is on a issue on my 1992 NSX
i recently purchased a NSX with a odd issue i havent been able to find anywhere else on this site or online.
When i turn on my headlights my passenger headlamp goes up fully with no issue however my driver side headlight goes up half way or just a little but more and when i turn off the headlights the passenger headlight goes down with ease. The driver side goes up fully then closes fully.
I am dumbfounded on what to do and what the issue could be.
Any help or ideas are welcome
Thank you all :encouragement:
Get a copy of the electrical section of the service manual (.pdf copies are available via Prime for free download if you search). On page 184 of the electrical section you will find the test procedure for the headlight retractor motor. In the test procedure you will find a retractor motor schematic and you will see that the retractor motor assembly includes a rotating contact assembly. The rotating contact assembly works a little bit like the parking contacts in a windshield wiper.

When the headlight is closed and also during the period that it is going up, switch terminal F is connected to B and C. Once the headlight is all the way up that connection opens up which tells the motor to stop running. I am suspicious that the rotating contact assembly may be worn or dirty and that the F to B/C connection is opening up when the headlight is part way up which is tricking the controller into treating the headlight as all the way up shutting the motor off. The down sequence is separate which is why the headlight continues to go up and then closes successfully.

The test procedure in the manual gives you the switch contact conditions with the headlight all the way down and all the way up. You need to check the contact positions while using the knob on the retractor motor to open the headlight from closed to full open (retractor motor disconnected off course). If you have long fingers I think you can do the complete down to up test without taking things apart. If you have fat stubby hands maybe find a 7 year old to help you! I essentially did this when I replaced a bulb years ago - its not fun. If contacts F to B/C opens up part way up, then the retractor motor switch is faulty. At that point you will need to remove the retractor motor and open it up to determine whether the contacts can be repaired. If the contacts operate as they should then the problem is someplace else and it is not immediately obvious where that someplace else is.

If you search on Prime using search terms such as 'headlight retractor motor repair' I think you may find one or two threads from about 8-10 years ago discussing retractor motor problems and repair. Its also possible that I saw the threads on the NSX Great Britain site in one of the blogs by Kaz so you could check there for further details.

Since you are a new owner, my best advice is to get a complete copy of the service manuals. You have a 28 year old car. You should expect that you are going to need the manuals in the future if you plan to keep the car.
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Thank you for the response. i will be doing the tests youve recommended once i get back home from University. I will keep you updated on my situation! currently searching the OM for possibly solutions to this aswell, luckily this PDF i found on NSX Prime is able to be CTRL F'd to quickly sort through the massive pile of papers.
Today i finally got around to removing and diagnosing the issue as described before. I had removed the motor that raises and lowers the headlight housing, lamp, and headlight cover. This was done following the tips from Old_Guy and was done from pages 23-182 to 23-184. After all was removed i disassembled the retactor motor. This was done by removing all Philips head screws first on the bottom round portion of the motor, After being opened i used electrical connector cleaner and cleaned off some of the parts in the motor that looked extra dirty as well as the 3 pins that were attached to the black plastic portion of the housing as these had what i thought to be an excess amount of grease. after this i removed the gear and cleaned the dirty portions of this piece too. Following this i removed the 2 phillips screws that held on the motor assembly and cleaned off the internals of this that looked corroded and lightly sanded them to bring back the copper look. I reassembled everything and found that the motor had the same issue. Would not go all the way up the first time but would go up then down after the lights were turned off. I removed everything again and with my limited knowledge of electrical components was stumped. I took the motor apart again and looked all over it for clues until i found the manual screw cap is removable and the screw shaft comes out of the black housing. After removal i found that there were two copper "arms" that were making contact with the screw shaft and with further inspection one of the connectors was worn down very badly. after trying to bend it to place to reach a little further to make the motor work properly it broke in my hands. Crap. I used a old inline fuse for my stereo amplifier and cut the copper fuse down enough to where it will fit in the slot where the worn part of the "arm" was. It fit loosely so i soldered it into place, reassembled everything and the headlamp motor works perfectly fine as if nothing was ever wrong! I know eventually the copper connector i added in will fail but the way i see it. it was already on its way out and needed a proper rebuild/ replacement. now time to look for a proper connector to eventually replace it. Whole process took about 4 hours working leisurely and testing every component. Hope this helps someone out there!
Nice when things work out, albeit perhaps temporarily. At least you know where a potential future problem lies.
Cool - Glad you were able to fix the issue.

Also, thanks for creating a video to help the community.