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Posted by: andys Sep 6 2015, 05:18 PM

The driver side headlight on my '75 914 won't go down when the switch is turned off. I tried probing around and found I can get it to go down by lightly pushing on the black sleeving that covers the green wire. I thought, ok, must be a broken wire, or a broken solder joint. I cut away the sleeving and I see what looks to be a capacitor (?).

I the accompanying photo, if I push on the capacitor lead adjacent to the motor terminal, I get nothing. If I push on the capacitor lead at the green wire, I get nothing. However, if I push on the capacitor lead close to its (black) body at the one o'clock side, the light goes down. I get nothing pushing on the seven o'clock side. Damaged capacitor perhaps?

I have a set of motors from a '72 or '73 (don't know if they work), but will I find the same capacitor under their sleeving? Would I be better off buying a new capacitor from the electronics supply? Does anyone know the value of the capacitor?

Thanks,

Andys


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Posted by: The Cabinetmaker Sep 6 2015, 05:22 PM

I've removed many headlight assemblies. Never seen one before.

Posted by: era vulgaris Sep 6 2015, 06:12 PM

That looks like a diode, but it's tough to tell from the blurry pics. Is the body a black cylinder with a silver ring around one end? If so, it's a diode. What letters and numbers are on the body of it? With the exception of resistors, which have color coded rings, most electrical components have a code printed on them that will tell you what they are if you are familiar with the codes.

Posted by: Maltese Falcon Sep 6 2015, 07:43 PM

Agreed, not a capacitor. Just out of curiosity have you checked the opposite side headlight motor green wire for a similar diode?
AFAIK, the diode just has a simple task of not letting the current flow back in the opposite direction. That being said, why not just try matching up a diode of like tolerance (if you can find a code on it) or match a similar 12v, rated at 30amp value diode for replacement. I'll check my 914 factory manual schematic and see what I can find.
Maybe Jeff B. will chime in here
Marty

Posted by: andys Sep 7 2015, 12:22 PM

Era Vulgaris,

That's as good a photo as I could take, as the diode is kind of a ways down in a hole. Yeah, wish I could read the numbers.


Marty,

I'd be great if your factory manual has the info on it. You're right, maybe a shout out to Jeff Blowsby. It's just such a hassle to remove the motor just to read the numbers, I'd prefer someone with the magic answer.

Andys

Posted by: Mike Bellis Sep 7 2015, 01:18 PM

Posted by: andys Sep 7 2015, 02:19 PM

Mike,

Thanks for the manual page. I see two capacitors on each motor at 30b and K, but I wonder what are their values?

Andys

Posted by: steuspeed Sep 7 2015, 02:22 PM

I see 4 diodes

Posted by: era vulgaris Sep 7 2015, 02:34 PM

You see two diodes on each motor.
This is a diode symbol:


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Posted by: Old Yella Sep 7 2015, 02:42 PM

I had the same problem. It had nothing to do with electrics. The lubrication at the pin of the rotating arm had dried up and the hole through which the pin goes was corroded. The arm which actuates the headlight was changes to metal in the later cars. This corrodes. Take off the black plastic cover and then the rubber boot and check to see if its all rusty in there.

I bought a second hand motor and took the actuating arm and the rotating arm off and fitted it to the existing motor. Job done.

Be very carful, you might loose your fingers if they are in the wrong place when the deadlight drops.

Posted by: andys Sep 7 2015, 02:43 PM

Ooops, Yeah I mean diodes!

Anyone care to take a stab at the values?

Andys

Posted by: era vulgaris Sep 7 2015, 03:15 PM

It'll say what it is on the body of the diode. For example,: 1N4007, 1N4004, 1N4148, etc etc will be printed on the body of the diode. You might have to pull it out and look at it, or get a magnifying glass. You can always just resolder it if you do have to pull it out.

Here's a good example using a 1N4007 diode of how the numbers are printed on there:



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Posted by: era vulgaris Sep 7 2015, 03:19 PM

On a side note that has nothing to do with the OP, if any of you are familiar with recording studio gear, certain revisions of the Universal Audio 1176 compressor use a 1N914 diode in its circuitry.


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Posted by: jim_hoyland Sep 11 2017, 12:43 PM

Old thread, but I have the exact same problem; anyone been in this situation


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Posted by: 914Wiggy Aug 19 2018, 01:27 PM

I am now! Anyone have an idea as to what it might be?

Posted by: jim_hoyland Aug 19 2018, 03:43 PM

There are several possibilities; if it’ a loose connection at the diode you may be able to see it. I used a fine pick to probe around and found it. The diodes have a black sleeve over them and may appear “folded”. Probe the green wire and see whether it’s loose; I initially pushed it and made contact with the diode. The light suddenly closed. ! Scary....

Posted by: sb914 Aug 19 2018, 04:15 PM

Watch your fingers!