Fixed Headlight that was not opening

SuperTopo

SuperTopo

True Classic
My son's '86 driver's headlight pod suddenly became unreliable. It would sometimes open fine, and other times would open 80% and stop. Then it got to where it would close and then not open at all.

I got in there and found that when it tailed to respond, if I helped it along by spinning the wheel on top it would continue and open/close like normal. A this point I assumed perhaps the bucket was mechanically jamming and would stall the motor sometimes. This theory made a little bit of sense as to why it would have suddenly come on and been getting worse and worse. So this weekend I pulled the adjustable linkage arm to see how badly the bucket was jamming. I found that while it didn't move freely, it wasn't jammed to where the motor shouldn't be able to get to full open/full closed.

I took the bucket out and found a fair amount of rust on the pivot shoulder bolts

1707077694736.png


So we steel wooled the shoulder bolts and cleaned up the bushings.

While the bucket was out, I ran the motor and found that it would not spin, I had to spin the wheel on top and then the motor would respond and drive to the end of travel, in either direction (up or down). Does this behavior reflect the bad diode issue or is it something else?

I replaced the motor with a spare and put it all back together, making sure to grease all pivots/joints. Now he has fully functional headlights again. Any thoughts on the possible root cause of the 'failed' motor are appreciated.
 
Found the issue:

One of the brushes wasn't fully in contact with the rotor:
1707173006306.png


Lots of corrosion in there. After pulling the brush to clean it out so it would move freely the spring fell to pieces:
1707173072441.png


Since I didn't have the right spring available, I cheated and fixed it with the pieces I had. It actually springs well like this (broken section of spring used to fill the gap).
1707173137051.png


BTW, I've heard wives tales of wiper motors being the same as headlight motors. I can tell you that at least the wiper motor out of an '86 is NOT the same motor. I took one apart hoping to steal a brush spring out of it. It's a smaller motor with smaller brushes. Similar in design sure, but not the same.

When reassembling it I used fishing line to pull the brushed out enough for the rotor to go in.

1707173453671.png


And I got rid of the flat screw heads and replaced them with Allen heads.

1707173300365.png


I then proceeded to try to test the motor out of the car by applying 12V to one of the plugs. The motor didn't respond so I applied 12V to the other set and promptly smoked a diode. 🤦‍♂️

So now I'll be doing the diode fix...
 
I don't have a pic but you should be able to test the motor without the diodes by putting 12V to the middle pin with 2 green wires on it while the earth is connected to the earth wire.

If you have that much corrosion, if you haven't already, give that earth to motor body a good clean, and check it with a multi meter. Motor body should connect to earth wire.
 
I would order a kit of various size springs on Amazon and replace the broken one. Parts are cheap, having to redo all that labor is not. IMHO.
 
You're right, which is why I got a new set of springs and replaced them. Here's the replacement next to the broken one:

1707710337300.png


And the fixed brushes:

1707710364177.png


I also soldered in a new diode for the one I smoked. I patched the wires that I inadvertently cut through the insulation with the wire brush like an idiot using shoe goo,

1707710414406.png
 
Yeah a cover would be nice. I am sure an enterprising person, maybe a 3d print?, could design something that uses the existing bolt holes. Just need longer bolts and maybe our diodes wouldn't die.
That said I recon a diode might last 20 years, I think that is about when mine died and needed replacing.
But a cover would look nice :)
 
Alex(Tenerife) said:
Yeah a cover would be nice. I am sure an enterprising person, maybe a 3d print?, could design something that uses the existing bolt holes. Just need longer bolts and maybe our diodes wouldn't die.
That said I recon a diode might last 20 years, I think that is about when mine died and needed replacing.
But a cover would look nice :)
Click to expand...
40 years and counting :)
 
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