85vettester

Ok I have a 85 vette and just finished putting new gears in the headlight motor, no problem. I put it all back on the car and now the lights are reversed, one goes up while the other goes down. There is only one way for the assembly to go back together. The motor is not the same as newer 87+ vettes and cannot be flipped etc... I can see in this forum that this is a common issue. It seems like the polarity has changed on the electric motor and now it runs backwards. The newer vettes are not the same so there is no way to flip the motor etc.... Someone . In the quote above memphiscop said he reversed the gray and green wires and that fixed the problem, so I tried it, and it went the right direction 1 time like the quote above and then the wires started melting so I unpluged it and reversed it back and still works backwards.. I am positive that it has been re-assembled the right way because it will only go back one way. I may have made a mistake by touching the electric motor inside the plastic housing with a screwdriver across the arm that holds the brushes down against the armater and that caused the polarity to flip. Does anybody have the answer to this problem? Is there a way to switch the polarity back by re-charging the armater with a battery somehow? Thanks for all your help and have a Merry Christmas.

oldalaskaman

ttt

c4cruiser

Have you recently replaced the isolation relay? The early C4's used this relay to change motor polarity to get the motors to run backwards to close the buckets.

If the isolation relay is working properly, there should be no reason to change the wiring.

85vettester

Like the others who had this problem, the motor was turning the right way before I started the repair. Now the motor turns clockwise when it should go counter-clockwise. Even if you adjust the door all the way closed as soon as I plug it in it just keeps going clockwise the wrong way so it just pops back open when I plug it back in. The relay was working before I started the repair. I replaced the gears and greased them and reinstalled the motor and it was working the right way but slow because I put too much grease on the gears but it was still turning the right direction just slow. . so I took it back apart and cleaned most of the grease back out but this time I was touching the motor with a screwdriver and now it runs nice and fast, just the wrong way. Reinstalled and now it runs backward. Thank You for your replys

oldalaskaman

ttt

85vettester

Left side, I may have touched a switch. I will double check in the AM. and see if I can see anything that looks like it was disturbed. I would go out to the garage tonight but I just ate so much Christmas dinner I cant move. lol Thanks Again

87 vette 81 big girl

I have had similar problems with my 87 Vert LH Driver's side headlight motor.

Turn the headlights on and the LH headlight closes.

Turn off the headlights and the LH Driver's headlight opens.

I also have tried reversing the Gray and green wires as you have, it opened and closed properly then, and the wires got real hot running up to the headlight motor.

Glad I had the hood open, unplugged the headlight motor in a hurry.

Switched the gray and green wires back into original location on the plastic weatherhead connector.

Traced all the headlight motor wiring and test lighted all respective circuits following the wiring diagrams from the Factory GM 1987 Corvette service manual.

All wiring OK. Power fed correctly at all times with headlight switch on or off.

I also changed out the isolation relay and LH headight relay with NOS GM Parts.

No fix yet.

This happened after I tore apart the LH headlight motor to repair it.

I have repaired the RH Passenger side headlight motor in the past with 100% SUCCESS.

I never had problems with stripped out plastic drive or driven gears stripping out.

I have Hella headlights in my car. They use a modern replaceable H3 Or H4 style replacement bulbs. Lucite Plastic Headlight housings I believe.

So the the headlights themselves are lighter than stock All glass units GM used.

The Problems I have had is water entry into the headlight motors themselves-corrosion.

Or the Permanent magnets themselves come loose from the Steel housing.

The Permanent Magnets then drag on the Armature at all times when the motor is in operation.

Then the headlights labor severe to open and close the headlight(s) with a dragging-grinding sound present.

The Ceramic based Permanent magnets were in held into place with small dabs Glue. Almost like Household Contact Cement Glue.

On the Passenger Side Headlight I reglued the magnets back into place with JB Weld epoxy glue.

Then Reassembled it carefully with a light coat of grease on all geartrain parts.

The RH Passenger headlight has worked flawless since 2007.

This past year in 2010 I started having problems with the Driver's Side Headlight on my 87 vert.

Heard the familiar dragging and grinding sound from it.

Tore it down, cleaned it. Reset the permanent magnets back into place in the steel housing with JB Weld.

Reassembled carefully with a light coat of grease on geartrain parts.

The Drivers headlight hasn't worked correctly since.

Repairs made on the LH healight motor at the end of November this year.

Snowed here in Illinois about the 2nd week of Dec. Parked my car for the winter. Figure I would tackle the LH headlight motor problem again this winter in my spare time or next spring.

After reading your post tonight with similar headlight problems...........

I am thinking I Mixed up the permanent magnets from their original Positions.

In other words, I have the NORTH AND SOUTH Poles of each magnet backwards from where the FACTORY had them.

That would cause the headlight motor to spin backwards when correct power polarity is fed to that motor.

I remember back to my Electronics Technology Classes Now In College over 20 years ago............

To Reverse an Permanent Field Magnet Motors Armature Rotation,

You Change the polarity of DC Power fed into the electric motor,

Or You change the Position of the Field Pole Magnets. North and South Pole Relations Respective.

I know now that I goofed up, repaired the LH headlight motor during my lunch break at work. Was in a rush.

Going to have to go back in this week and correct the Permanent magnet Pole Positions. Just need an old fashioned COMPASS to locate the NORT AND SOUTH POLES...............

I know this a Very LONG Post and reply back.

Does this make sense to You ?

There is a locating pin or Notch cut into the Steel permanent magnet housing that mates up to plastic headlight housing motor half.

Is it set back in correctly? Or is the Steel Magnet housing flipped around 180/ backwards(LEFT TO RIGHT). The North and South poles would be reversed then.

The electric motor would then spin backwards from normal rotation with correct polarity power fed to it.

Its worth a look again inside of the troublesome headlight motors of both are Corvettes.

Brian R.

red 90

how many wires and what color are they?

oldalaskaman

ttt

87 vette 81 big girl

3 - wire headlight motors used on the 1984 - 1987 Vettes.

Green, White, and gray color coded wires running to the Weather pack connector.

They could be some other color if the weather changed or you consumed too much alcohol this holiday season and take another look trying to focus your eyes working on your car. LOL

oldalaskaman

ttt

87 vette 81 big girl

OK. I was just kidding with you.

Happy Holidays By the way !

I have a pretty good photographic memory if I have worked on a car or subpart off of it in the past.

I remember Wire Color codes too.

I do believe I have the permanent field magnets glued in backwards from what the factory had them at.

The motor will spin the opposite direction and the internal stop limit switches wont work at all.

No amount of external wiring will correct the problem.

On a Car starter motor, like the old and heavy AC Delco MT10 series starters, used on 1984-1987 vettes and countless other GM Vehicles built prior to 1984........

If You Reverse the polarity of the Outside Electromagnetic fields, the starter motor will spin the wrong direction.

Was actually done that way with boats with daul small block or bigblock engines.

One engine spins normal rotation and the other opposite direction.

Starter motors spin each in opposite direction of each other.

For the pair of Counter rotating props so the boat will go in a straight line, and not in a big circle.

BR

JackDidley

Must be a headlight virus going around. Mine just went on the fritz a couple weeks ago.

85vettester

Here's what I've learned:

A) Dont cross the green and grey wires unless you are ready for a BBQ.
B) To change the direction of the left motor make sure the Rubber tab on the Plastic motor housing is lined up with the mark Opposite of the notch on the armature housing. Notch goes down.
C) Now I need a new motor.

I know this post will help many C4 Corvette owners with the headlight motor direction issue.

If anyone has a good deal on a Left Side motor let me know with a PM thanks. Scott (85vettester)

rcle1220

I have a 1988 Vette. I bought a new after market left (driver's) side motor assembly and installed it. First off the motor ran backwards and I tried tests and everything I could think of (took it off and back on 3 times) and then I read about reversing the wires. Mine only has two wires, a green one and a white one. Once I reversed them on the motor and plugged them in all worked good. I got nervous though when I read the wires will get hot doing this so I operated the light switch at least 20 times but the wires never heated up. Am I okay now or should I undo what I did? Hate the thought of going to a dealer at the fees they'll charge me so any info will be greatly appreciated.

Tact

http://forums.corvetteforum.com/foru...s-or-more.html