Can't get Driver headlight to cooperate - NA

[Jeff]

Any of you seen this or have any recommendations for a fix? I typed up my issue and a couple follow ups here:
http://forum.miata.net/vb/showthread.php?t=404282

This guy is also have the same problem:
http://forum.miata.net/vb/showthread.php?t=396428

[Jeff]

Any ideas? Anyone willing to take a look for me?

[Titus]

This may help:
headlight.JPG

[Jeff]

Awesome, thanks that'll be a big help in my testing tonight.

[Jeff]

Well, turns out I don't have the right stuff to get a solid jump to those pins, they are damn SMALL! I had planned on jumping the female side and thought I could do it tonight. I'm going to run through this again tomorrow.

Time for some updates.

I pulled the harness apart to the "bad" headlamp motor and it looked pretty good. I went ahead and cleaned it up with some contact cleaner on both sides, hooked it back up - no dice.

I pulled the relay under the dash and fully disassembled. It also looked pretty good, but I cleaned it anyways - reinstalled - no change.

Checked the ground block I posted above - no broken wires, no major rust. Hit it with some cleaner just in case - no change.

I don't have a multimeter so I'll have to check the signal coming from the harness tomorrow night when I attempt to directly jump the motor.

Now away from the failures and on to some new behavior.

If I manually set the light in between up and down, and then put them "down" - the bad light will go all the way up, then all the way down - so the motor can definitely raise the light no problem.

After you do this, and then bring them back up, you can see the bad light wiggle, then nothing. No more movement until you put it back in the middle, and then you can make it wiggle again.

In the middle of my testing, I set the stalk to parking lights, then flashed the brights - the "bad" light flipped halfway up, then went back down. I could never make it do that again.

[AlanP1964]

FWIW you can get a cheapie multi-meter at Harbor Freight for under $5. It's not a Fluke type quality meter but works fine for DIY stuff.

[Jeff]

Yeah, I just don't have one at the moment. I'll be at my buddies shop to work on that part tomorrow. Wanted to post the details from tonight to see if it raised any eyebrows for anyone.

[AlanP1964]

If it turns out to be the motor, I have a spare one you could have. My driver's side wouldnt retract. Someone on the pointy board sent me one for free. After removing my old one, I discovered a broken wire from the motor to the harness plug. I'm assuming if the wire were soldered back together etc, it would probably work fine.

[Jeff]

Awesome. At this point I'm 90% sure it's a problem with the motor, I just have to test the harness for proper voltages to be sure. What I'm thinking is there is a problem with the relay inside the motor that either shorting and sending a constant "close" signal, or the "open" diode is bad. Either way - new motor should fix the issue. I should know tonight what I need to do.

This thread is what I'm basing this off of: http://forum.miata.net/vb/showpost.p...20&postcount=8

[Jeff]

Fixed my headlight last night!

I ended up getting out the multimeter and testing out the car side of the motor harness using the pin layout posted above.

The car was supplying all of the proper voltages to the harness, and all contacts were clean, so I knew it was something past this point - located within the motor.

I pulled the motor and ripped it apart. I only dismantled the bottom section where the wires are, not the top black section with the adjustment knob.

After reading this post: http://forum.miata.net/vb/showpost.p...20&postcount=8 - I decided pulled out the multimeter again to test my existing diodes. All of them checked out fine so I was kind of stumped. Inside this piece, there are 3 pieces of metal that use tension to make contact with a large spinning wheel that moves with the motor. These 3 pieces of metal are the "up" "down" and one that goes straight to the motor. At this point, I'm guessing the "up" connection is just poor after years of operation.

I used some sandpaper to clean/scuff up the 3 prongs, and did the same to the large metal wheel that they contact. I then wiped away as much of the old grease that I could, re-coated everything in some fresh dielectric grease, and reassembled.

Hooked everything back up in the car and viola! Everything functioned perfectly. Just wanted to document this for any future members who might find they have a problem with only one headlight, and don't feel like spending $200 on a new motor. This was a completely free fix :)

[sammm]

Good work!

[Jeff]

Do I get my TCB license back?

[AlanP1964]

Do I get my TCB license back?

That and the official DFWMiata.com license of resident headlight motor rebuilder expert! :)