Someone once said something to the effect of "The 84-86 headlight system is a beautiful ballet of relays, motors and switches." I cant remember who it was, but I couldn’t have said it better myself.
I’m going to try to explain what happens when the headlights go up and down.
Accept the next three statements and then I’ll show you how it all works. Power to make the motor go down is always on when the headlight switch is OFF. Power to make the motor go up is always on when the headlight switch is ON. What stops the motor from turning is the limit switch.
[This message has been edited by buddycraigg (edited 12-11-2007).]
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09:32 PM
PFF
System Bot
buddycraigg Member
Posts: 13606 From: kansas city, mo Registered: Jul 2002
The parking lights instantly come on. The headlight bulbs instantly come on. The isolation relay is energized. The isolation relay energizes both of the motor relays.
Now the 3 wires to the motor take on a different purpose. The blue wire is dead. The green wire is powered. The gray wire is ground.
The armature starts to spin. Since the worm gear threads on the armature look like the threads of a screw the armature moves about 1/8” to the left before the metal gear starts to turn.
The limit switch goes to it’s “at rest” position. Notice the air gap between the fingers on the armature. Red arrows.
And both of the contacts of the limit switch are closed. Blue arrows.
As the armature is spinning (as if it would be rolling towards you in this pic) The metal gear is turning counter-clockwise The plastic gear is turning clockwise.
Eventually the headlight is all the way up and the linkages hit their respective stops on the assembly. Now the gears cannot turn anymore. But the armature still wants to spin because there is still power. So the screw like threads of the armature force the armature to move another 1/8” to the left And the fingers snap open the bottom limit switch. Killing the power to the armature.
[This message has been edited by buddycraigg (edited 11-19-2005).]
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09:35 PM
buddycraigg Member
Posts: 13606 From: kansas city, mo Registered: Jul 2002
Now you are home and you want to turn off your lights
So you turn OFF the headlight switch.
The parking lights instantly go out. The headlight bulbs instantly go out. The isolation relay is turned off. The isolation relay turns off both of the motor relays.
Now the 3 wires to the motor take on a different purpose again. The blue wire is powered. The green wire is ground. The gray wire is dead.
The armature starts to spin. Again because of the screw like threads on the armature It moves about 1/8” to the right before the metal gear starts to turn and the limit switch goes to it’s “at rest” position.
As the armature is spinning (as if it would be rolling away from you in this pic) The metal gear is turning clockwise The plastic gear is turning counter-clockwise.
Eventually the headlight is all the way down and the linkages hit their respective stops on the assembly. Again, the gears cannot turn anymore. But the armature still wants to spin because there is still power. So the screw like threads of the armature force the armature to move another 1/8” to the right And the fingers snap open the upper limit switch. Killing the power to the armature.
now you’re back to where you started.
[This message has been edited by buddycraigg (edited 11-19-2005).]
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09:36 PM
buddycraigg Member
Posts: 13606 From: kansas city, mo Registered: Jul 2002
Then the armature will keep spinning because the wide part of the metal gear doesn't stop turning. And it has to stop so the the armature can screw in or out to snap open the limit switch.
[This message has been edited by buddycraigg (edited 11-19-2005).]
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09:53 PM
wanobi Member
Posts: 1257 From: Rockdale GA Registered: Sep 2005
yea the pics and description of everything is very helpful for a dummy like me. I'm going to rebuild my driver side headlight and use your gen 1 thread. It's great!
Josh
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10:19 PM
btklassy Member
Posts: 57 From: Mound, MN, USA Registered: Dec 2001
yes, if you have the motor bolted to the assembly, and the linkages attached. after the headlight bucket is all the way up or all the way down. the knob will eventually stop turning.
BRB i want to check something.
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10:49 PM
PFF
System Bot
buddycraigg Member
Posts: 13606 From: kansas city, mo Registered: Jul 2002
i just checked. it takes 121~123 turns to go from full up to full down or vise verse. you can here the limit switch "click" when you start turning and then again when it reaches the end.
and i just remembered that i forgot to plug the blue wire back in. so now i have to go back outside.
[This message has been edited by buddycraigg (edited 11-19-2005).]
Originally posted by buddycraigg: Someone once said something to the effect of "The 84-86 headlight system is a beautiful ballet of relays, motors and switches." I cant remember who it was, but I couldn’t have said it better myself.
Yeah... that's one way to put it. POS is another.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurasic Park)
nope just thought that through a little better my roblem would be in that headlights relay
it could be the relay, swap the two motor relays with each other. they are bolted next to each headlight.
it could be the contacts on the bottom limit switch are burned.
it could be a bad connection where the blue wire plugs in together. it looks like a old fashoned glass fuse holder. EDIT i think it's the same type of connect for a single wire oxygen sensor.
[This message has been edited by buddycraigg (edited 11-20-2005).]
Oddly enough, on Jane's 84, those "P'sOS" have worked flawlessly up till this year. Mine still work fine. Collectively, 2 cars=4 headlights=80 yrs of service. Yeah, that's just a terrible record of service.
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12:20 PM
Gordo Member
Posts: 2981 From: East Guilford, NY, USA Registered: Mar 2002
someone needs some gen 1 help... bump to keep this thread alive
You, buddycraig are very correct sir! I rebuilt my headlights about 8 months ago with Rodney's brass gear kit and it has worked fine until about 2 weeks ago. On the first occasion, I pulled into Safeway at night, turned my headlights off but the passenger side stayed up. About a week later, while leaving Whuffo's house in the rain, he turned on my headlights 3 different times but the passenger side refused to go up. (Whuffo was driving my car home after working on it) Anyways, I am always able to fix the problem by either turning the knob on top of the headlight motor OR turning the headlight switch on and off several times. One interesting note is that when the passenger side is "stuck" either up or down, the headlight knob begins to get very warm! Whuffo said my problem is the limit switches. If it is, do you know who might have them cheap? I know Rodney has them but they're still expensive. ($78.00 for both motors) Do you know who has them cheaper? What is the AC Delco p/n? Thanks, Kit (86 GT)
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02:28 AM
Max The Chainsaw Member
Posts: 1140 From: Danville, IL Registered: Oct 2000
LOL now theres a man who thinks like I do. I keep 3 sets of Gen 2 motors, with harnesses and control boxes on hand. First thing I do to my fieros is remove Gen 1 headlights and install Gen 2. last 2 cars had perfectly working Gen 1's in em and I replaced them. The Gen 2's are that much better IMO.
Max
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06:18 PM
John Boelte Member
Posts: 1012 From: Indianapolis, IN, USA Registered: Jun 2002
LOL now theres a man who thinks like I do. I keep 3 sets of Gen 2 motors, with harnesses and control boxes on hand. First thing I do to my fieros is remove Gen 1 headlights and install Gen 2. last 2 cars had perfectly working Gen 1's in em and I replaced them. The Gen 2's are that much better IMO.
Max
can i have the right hand motors? hell if they were working and the plastic gear may be ok, i'll take them all... but the right hand shaft is in higher demand.
how much would you want for them, and or i can issue a UPS call tag.
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08:37 PM
bonzo Member
Posts: 1350 From: Jacksonville, FL, USA Registered: Jul 2003
Another problem you might run into with these motors is the thermal switch. ( The glass bulb looking thing) It will remove power before it makes the limit switch. Then when it cools down it will close the circuit and the motor wont have the momentum to make the switch and the thermal switch opens again. Whew. It will keep doing this untill your battery is dead. The easy way to see if this is the problem is to watch your knob when you turn off the lights. (That kind of sounds funny) If the knob moves then stops over and over again, your thermal switch is too sensative, you"ll need a new one.
Yeah I found this out the hard way. My plastic cap on top of my driver side motor actually melted and bubbled after my motor glass circuit breaker failed.
Bump, 'cause I'm dealing with these problems right now on my wife's 86 Couple. I'm THIS -> | | <- close to pulling the entire assembly out and converting to 87-88. I have a large moving box full of headlight motors and assemblies. One trip to the junkyard for the wiring harness and relays, and it's adios 86 POS.
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12:15 PM
Whuffo Member
Posts: 3000 From: San Jose, CA Registered: Jul 2003
The early design headlight motors work well and can be very reliable. They can be a little tricky to troubleshoot, though - the operational "logic" is implemented in relays and switches and creative mechanical design.
But they CAN be rebuilt and work perfectly - and I believe it's easier than converting the headlight system to the later design.
And there is an advantage to the older design; when the little "bumpers" disintegrate, the headlights will still go up and down - not very gracefully, but they'll work. The later design motors - when the bumpers fail the light won't go up at all. You can't crank it up with the manual knob either. That's not good design...
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07:35 PM
PFF
System Bot
buddycraigg Member
Posts: 13606 From: kansas city, mo Registered: Jul 2002
You, buddycraig are very correct sir! I rebuilt my headlights about 8 months ago with Rodney's brass gear kit and it has worked fine until about 2 weeks ago. On the first occasion, I pulled into Safeway at night, turned my headlights off but the passenger side stayed up. About a week later, while leaving Whuffo's house in the rain, he turned on my headlights 3 different times but the passenger side refused to go up. (Whuffo was driving my car home after working on it) Anyways, I am always able to fix the problem by either turning the knob on top of the headlight motor OR turning the headlight switch on and off several times. One interesting note is that when the passenger side is "stuck" either up or down, the headlight knob begins to get very warm! Whuffo said my problem is the limit switches. If it is, do you know who might have them cheap? I know Rodney has them but they're still expensive. ($78.00 for both motors) Do you know who has them cheaper? What is the AC Delco p/n? Thanks, Kit (86 GT)
oops missed this post. no, i dont know of anyone that sells them other than rodney. luckily for me i have a lot more limit switches than i do gears so i'll probably never have to by them
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08:27 PM
Aug 8th, 2006
fierobear Member
Posts: 27083 From: Safe in the Carolinas Registered: Aug 2000
I've been having problems with the right headlight motor. It was doing the "twitching" deal, and sometimes wouldn't go down or up. If I read Buddy's threads correctly, both limit switches shouldn't be touching at the same time:
What the heck is going on inside there?
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10:08 PM
buddycraigg Member
Posts: 13606 From: kansas city, mo Registered: Jul 2002
I cranked the knob all the way, put it back together, and it seems to be working. I ran them up and down several times, and there was no twitcing. So I ran away from the car as fast as I could, before it could change it's mind.
I think they're working. Thanks for the great write-up, Buddy.
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11:25 PM
Aug 9th, 2006
buddycraigg Member
Posts: 13606 From: kansas city, mo Registered: Jul 2002
So if I'm understanding this right, the armature actuates the limit switches when it meets resistance? So if I wanted the headlight to only go halfway up, I could put some sorta mechanical stop on there and it wouldn't hurt anything? I ask because one of the things I have been thinking about is doing some sorta low profile/hid/projector headlight conversion.
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01:30 AM
fierobear Member
Posts: 27083 From: Safe in the Carolinas Registered: Aug 2000
You're probably right. Fierobear needs to clean those limit switch contacts; when they get dirty they'll cause all kinds of misery.
It shouldn't be too bad. I might even be able to do it on the car, since there is an inspection plate over the contacts. If not, I've taken the damn thing in and out so much, I could probably do it in my sleep.
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02:28 AM
Aug 16th, 2006
buddycraigg Member
Posts: 13606 From: kansas city, mo Registered: Jul 2002
So if I'm understanding this right, the armature actuates the limit switches when it meets resistance? So if I wanted the headlight to only go halfway up, I could put some sorta mechanical stop on there and it wouldn't hurt anything? I ask because one of the things I have been thinking about is doing some sorta low profile/hid/projector headlight conversion.
that is correct. i've head it called "sleepy eyes"
becareful while you're playing with the system. although the motors are high speed low toqure, the mechanical advantige of the gearing could hurt you if you have a finger where it shouldn't be.
[This message has been edited by buddycraigg (edited 08-16-2006).]
