Headlight goes up. Won't go back down., What is broken here? Options

[VegasRacer]

Both headlights pop up as the German engineers intended. Only the left one returns to the down position with the dashboard knob. The right one will go down using the knob on be back of the motor.
What is causing this malfunction? (IMG:style_emoticons/default/confused24.gif)
There are no obstructions. The usual suspect pivot is intact.
Is this a sign the headlight motor is going bad?

[fiacra]

Have you tried swapping out the relay for a known good one yet? Easy to switch left and right and see if the problem "magically" switches sides.

[VegasRacer]

Have you tried swapping out the relay for a known good one yet?

Just swapped sides for the relays.
The symptoms did not change.

[barefoot]

There are limit switches that reverse current to do the up & down functions. These are located in the mechanism.

[ClayPerrine]

This should help:

914World - How your headlight motors work.


I just looked at the date on the initial post. That was 21 F$%K#@G years ago! (IMG:style_emoticons/default/slits.gif)

[GeorgeKopf]

I am in the middle of refurbishing my headlight motors and I have them all apart.

I'll add pictures when I get a chance.

The motor turns a screw gear that meshes with a round gear. On the face of the round gear is a conductive metal plate. On the inside of the mechanism are three electric pickups.

On the four motors that I have taken apart, the problems seem to be:

1. Corrosion on the conductive metal plate interfering with the pickups.
2. Corrosion on the motor's spindle bearing for the screw gear.
3. Frayed wires entering the motor's body.

Your symptoms sound, to me, like corrosion on the round gear's conductive metal plate.

George

[Ron914]

Have you tried swapping out the relay for a known good one yet? Easy to switch left and right and see if the problem "magically" switches sides.

I didn't know that you can do that .This is a great trouble shooting tipi I ever run into this problem .
(IMG:style_emoticons/default/smile.gif)

[fixer34]

I concur with the electric wiper/contacts inside the gear assembly. Have never had mine apart, but it appears to be a similar design to windshield wipers. I had to disassemble/clean the gearbox in a couple Chevy SUVs. Wipers would stutter, stop, not park, etc. Cleaning the contacts and applying a light coating of grease got everything working.

Clay, I looked at your wiring digrams. If I read them right, the headlight motors will not work without the ignition being on.
My -6 pops up the headlights and turns on front/back/side parking lights without the key. Headlights do not come on though, as expected.

[Maltese Falcon]

John @VegasRacer we had a similar problem and after process of elimination it turned out to be a tired 50+ year old (left side*) electric motor.
*Rights and lefts are dedicated/can't be swapped. I had a few spare headlight motor assemblies around in the workshop>>found a good working left but with chopped wires. While re-wiring, soldering, shrink tubing, I did open up the mechanism for a look. I found that all of the lube that usually sits on the printed circuit 'Disc (assists the moving points to glide while operating) had migrated into a big lump at the bottom. Basically cleaned up the dirty old grease, cleaned the disc and reapplied a thin film of lube; then reassembled. If you do buy a surplus headlight assembly I would def inspect/tune up if needed (IMG:style_emoticons/default/thumb3d.gif)

[Ron914]

I concur with the electric wiper/contacts inside the gear assembly. Have never had mine apart, but it appears to be a similar design to windshield wipers. I had to disassemble/clean the gearbox in a couple Chevy SUVs. Wipers would stutter, stop, not park, etc. Cleaning the contacts and applying a light coating of grease got everything working.

Clay, I looked at your wiring digrams. If I read them right, the headlight motors will not work without the ignition being on.
My -6 pops up the headlights and turns on front/back/side parking lights without the key. Headlights do not come on though, as expected.

FWIW my 1976 -when I operate the headlights with the key off the running/parking lights come on but no lift or operation of the headlights.

[Tonyooc]

I had a bad ground wire up at the headlights. Mine did the same thing.

[ClayPerrine]

I concur with the electric wiper/contacts inside the gear assembly. Have never had mine apart, but it appears to be a similar design to windshield wipers. I had to disassemble/clean the gearbox in a couple Chevy SUVs. Wipers would stutter, stop, not park, etc. Cleaning the contacts and applying a light coating of grease got everything working.

Clay, I looked at your wiring digrams. If I read them right, the headlight motors will not work without the ignition being on.
My -6 pops up the headlights and turns on front/back/side parking lights without the key. Headlights do not come on though, as expected.

FWIW my 1976 -when I operate the headlights with the key off the running/parking lights come on but no lift or operation of the headlights.

If your headlights are down and the key is off, they won't go up or turn on. But if they are up and you turn them off, they will go down. If you manually turn the knob on one headlight to make it start going up, it will go up and immediately go back down. So the motors are powered all the time, but the power to raise them is only powered on when the headlights and the key are on.

[GeorgeKopf]

This is the gear mechanism with the conductive plate. You can see the three tracks that the pickups ride on.


Here is a close up of the conducive plate. Notice the white plastic spaces on the inside and outside. This is where the motor stop moving in one direction.


Here is a close up of the three pickups.


BTW: I have six old headlight motors (3 for each side) and only one of them works. I took four of them apart and they are different in their construction. The electric internals, the shape of the screw gear and the external connectors are different. Not sure if this is "older" vs. "newer" versions but they have the same part numbers.

George