Headlight Motor Direction Problem
Thread Starter
Rennlist Member
Joined: Nov 2009
Posts: 8,663
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From: Dubuque, IA
Headlight Motor Direction Problem
I was reading Fred R's thread on his headlights and I have a somewhat similar question but want to get opinions on it in the event it is simply an adjustment that I need to do.
My headlights will, when the car is not running but ignition on, go up and then pull back a bit. When I have the car running they go up all the way all the time.
Today, when i turned them on, the motor ran backwards and impacted my a/c condenser. it didn't put a hole in it, thank goodness, just a large nick. AC still works.
When I try to turn the motor back by hand via the **** with the lights down, it gets to the bottom from the wrong side (because it seems to have over rotated) and then the motor fights me and won't let me rotate it to the proper side for correct direction operation until I turn the key off. Then I can get the motor manually back to the other side via the manual ****.
Is there an adjustment on the headlight motor to keep it from over rotating down and thus not hitting the compressor when it tries to come up?
The circlips are all in place.
Thanks
My headlights will, when the car is not running but ignition on, go up and then pull back a bit. When I have the car running they go up all the way all the time.
Today, when i turned them on, the motor ran backwards and impacted my a/c condenser. it didn't put a hole in it, thank goodness, just a large nick. AC still works.
When I try to turn the motor back by hand via the **** with the lights down, it gets to the bottom from the wrong side (because it seems to have over rotated) and then the motor fights me and won't let me rotate it to the proper side for correct direction operation until I turn the key off. Then I can get the motor manually back to the other side via the manual ****.
Is there an adjustment on the headlight motor to keep it from over rotating down and thus not hitting the compressor when it tries to come up?
The circlips are all in place.
Thanks
Nordschleife Master
Joined: Jul 2011
Posts: 5,662
Likes: 26
From: North Country
Jeff,
Remove the linkage and then have someone operate the headlight motor by turning on then off. You visualize the motion. On our S4's it should be semicircular motion back and forth. Mark the splined shaft if needed. If you have that, realign the linkage in the usual fashion. Also check status of the splines and the linkage that operates with it.
Remove the linkage and then have someone operate the headlight motor by turning on then off. You visualize the motion. On our S4's it should be semicircular motion back and forth. Mark the splined shaft if needed. If you have that, realign the linkage in the usual fashion. Also check status of the splines and the linkage that operates with it.
Team Owner
Joined: May 2004
Posts: 31,335
Likes: 4,290
From: Philly PA
Is the headlight relay original or a replacement part?
I had a similar issue with my lights going past the normal setting and then aimed a few degrees higher than where they normally stopped.
I installed a good used HL relay problem solved.
With the motor going backwards there may be issues with the motor internals.
But if you follow Craigs advice to remove the arm from the motor and cycle it this may cure the issue,
maybe the arm did come loose
I had a similar issue with my lights going past the normal setting and then aimed a few degrees higher than where they normally stopped.
I installed a good used HL relay problem solved.
With the motor going backwards there may be issues with the motor internals.
But if you follow Craigs advice to remove the arm from the motor and cycle it this may cure the issue,
maybe the arm did come loose
Nordschleife Master
Joined: Jul 2011
Posts: 5,662
Likes: 26
From: North Country
When I try to turn the motor back by hand via the **** with the lights down, it gets to the bottom from the wrong side (because it seems to have over rotated) and then the motor fights me and won't let me rotate it to the proper side for correct direction operation until I turn the key off. Then I can get the motor manually back to the other side via the manual ****.
It is showing the the motors internal position sensors are functioning by not allowing even manual excursion from where it thinks the light should be.
Reset the linkage and give her a run. I bet the linkage slipped on the splines. Have a look at them.
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Thread Starter
Rennlist Member
Joined: Nov 2009
Posts: 8,663
Likes: 428
From: Dubuque, IA
I looked at the linkage and can see how it transcribes an arc. I set it at what appears to be the bottom of the arc and tried it. When I assmebled it, it went to the top and past a bit. Then when I turned off the lights, it tried to continue around and hit the condenser again. With the arm off my motor when you turn it on, the splined shaft goes round and round and round and the headlights blink on/off on/off until you turn the light switch off. When you turn it off, it goes to a certain point and stops. Is this normal or is there a limit switch in the headlight travel path that says "whoa!" and the motor stops there and reverses direction when switch is turned off?
Do you put the arm on at the up position or the bottom position? I pulled the entire linkage apart and have all the clips and washers and arms on my bench. I have tried both ways but am missing something. Don't want to hit the condenser too many more times or I'll end up needing a new one. Doesn't leak yet but has some nice gouges.
Do you put the arm on at the up position or the bottom position? I pulled the entire linkage apart and have all the clips and washers and arms on my bench. I have tried both ways but am missing something. Don't want to hit the condenser too many more times or I'll end up needing a new one. Doesn't leak yet but has some nice gouges.
Last edited by jeff spahn; Sep 3, 2013 at 09:48 AM. Reason: add stuff
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Nordschleife Master
Joined: Jul 2011
Posts: 5,662
Likes: 26
From: North Country
Jeff,
This must be making you near insane, as well as concerned.
What I do to set it is linkage off, engine on (I want it in running operational state), assistant puts light switch on and I watch the motor spin there, pull up the lights by hand and have my assistant hold them in EXACTLY THERE FINAL UP POSITION, I then set the linkage on in the most extended position. I even threw a dab of Blue Loctite on the spines.
This must be making you near insane, as well as concerned.
What I do to set it is linkage off, engine on (I want it in running operational state), assistant puts light switch on and I watch the motor spin there, pull up the lights by hand and have my assistant hold them in EXACTLY THERE FINAL UP POSITION, I then set the linkage on in the most extended position. I even threw a dab of Blue Loctite on the spines.
Pro
Joined: Dec 2010
Posts: 703
Likes: 3
From: Palgrave, Ontario, Canada
I have exactly the same issue on my '90 euro, but have yet to open up things to figure it out, so am hoping to learn more in this thread.
The headlights raise past the top of the arc and continue until the arm strikes the A/C condenser coil, at which point they stop, having moved about 250 degrees. It seems like the mechanism is looking for a hard stop feedback to be detected to halt the motor, but is failing to find it and continues until the arm hits the coil. As I understand it on a '90 the motor reverses direction to lower the lights, so this means that the normal arc of operation must be less than 180 degrees, and that something has to stop it, which is not happening.
I am not sure if the normal stop is electrical or mechanical. Being a euro, the headlight angle is adjustable, which would seem to require that the upper stop point be changed. PET shows two electrical extensions coming from the height adjustment switch. If they were connecting to the lift motor, I assume only one would be required, so I am inclined to think that they must affect a mechanical stop in each fender, but at this point I'm guessing. I also suspect the relay, which likely 'processes' any feedback signal.
The headlights raise past the top of the arc and continue until the arm strikes the A/C condenser coil, at which point they stop, having moved about 250 degrees. It seems like the mechanism is looking for a hard stop feedback to be detected to halt the motor, but is failing to find it and continues until the arm hits the coil. As I understand it on a '90 the motor reverses direction to lower the lights, so this means that the normal arc of operation must be less than 180 degrees, and that something has to stop it, which is not happening.
I am not sure if the normal stop is electrical or mechanical. Being a euro, the headlight angle is adjustable, which would seem to require that the upper stop point be changed. PET shows two electrical extensions coming from the height adjustment switch. If they were connecting to the lift motor, I assume only one would be required, so I am inclined to think that they must affect a mechanical stop in each fender, but at this point I'm guessing. I also suspect the relay, which likely 'processes' any feedback signal.
Nordschleife Master
Joined: Jul 2011
Posts: 5,662
Likes: 26
From: North Country
The motor shouldn't be looking for a hard stop. Its internal position sensors should sense the traverse 180 deg to the other up or down position and then stop of its own accord. Then signal sent to relay regarding its achieved position. That's why they go up, stop, and then the light illuminates. I don't know if a Euro is different.
Jeff, if you set it as described it should work. If not internal motor issue. Detach the large cylindrical harness above the motor and raise/lower by hand. Illumination will still work from the switch. I had to do this for a spell when I had a similar issue.
Jeff, if you set it as described it should work. If not internal motor issue. Detach the large cylindrical harness above the motor and raise/lower by hand. Illumination will still work from the switch. I had to do this for a spell when I had a similar issue.
Team Owner
Joined: May 2004
Posts: 31,335
Likes: 4,290
From: Philly PA
Maybe Alan will chime in here,
from the what your reporting,
there may be a diode thats burned out in the motor thus letting it continue to run,
Alan was addressing this issue for someone else a few days ago in the mean time dont let the arm hit the condenser it will hole it
from the what your reporting,
there may be a diode thats burned out in the motor thus letting it continue to run,
Alan was addressing this issue for someone else a few days ago in the mean time dont let the arm hit the condenser it will hole it
Rennlist Member
Joined: Dec 2002
Posts: 5,283
Likes: 52
From: Australia
I dont follow how the arm can hit the condenser with all the clips in place ??? Does the motor actually change direction between up and down?
I had an issue early in my ownership, which I had to fix with a new relay, having checked inside the motor case and the 4 wire connector.
jp 83 Euro S AT 55k
I had an issue early in my ownership, which I had to fix with a new relay, having checked inside the motor case and the 4 wire connector.
jp 83 Euro S AT 55k
Nordschleife Master
Joined: Jul 2011
Posts: 5,662
Likes: 26
From: North Country
Internal motor/stop point sensor malfunction resulting in abnormal excursion.
or
The union of the linkage to the splined motor shaft jumps a spline back and forth resulting in abnormal excursion.
Internal motor malfunction more likely.
Now it's for Alan.
