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Hi all, I have a head light question on 71 vw. The driver head light does not work and I tried 3 different lights. I have voltage at the light socket, but it acts like a positive ground system because when I hook the volt meter up I need to put the hot lead in the center and the ground on the right or left to get 12 volts? I cleaned what looked to be the grounds on both sides, but still no light. Could it be a short in the switch? However, the other side works. Any ideas are appreciated.
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vw headlight?
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Banjo
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Sounds like a ground issue. in a 3 terminal headlight socket one wire is lo-beam, one is hi-beam, and one is ground. A test light on a good body ground should light up on the lo and hi wires with the switch on, and the dimmer in the respective position. Putting the tail of the test light on a battery positive terminal somewhere, should light the tester if you probe the ground wire in the socket. If no light, look for a bad ground.
Also remember you can get a 12 volt reading on a circuit with enough resistance to not let the load (in this case the bulb) work. If the ground checked out, then look for high resistance in the feed wire.
Also remember you can get a 12 volt reading on a circuit with enough resistance to not let the load (in this case the bulb) work. If the ground checked out, then look for high resistance in the feed wire.
D
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And on a veewee, do NOT depend on the wing (fender) to be ground!
Run a new ground wire to the main body, and knowing what state you are in, clean the rust off!
I remember guys bringing veewees in with no lights......and the grounds looked like they were there.....fresh paint.....fibreglas fenders.
I have, in the past with German high-iron content bodies, run ground wires clear back to the battery.
The rust was so bad I didn't trust the ground path to be complete!
Run a new ground wire to the main body, and knowing what state you are in, clean the rust off!
I remember guys bringing veewees in with no lights......and the grounds looked like they were there.....fresh paint.....fibreglas fenders.
I have, in the past with German high-iron content bodies, run ground wires clear back to the battery.
The rust was so bad I didn't trust the ground path to be complete!
TR3driver
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I think you are looking at the connector wrong. The ground terminal is on one side, not the center. Looking at the socket, with the two parallel tabs on each side and the other tab on top, the ground should be on the right. (This isn't my photo, just one I found)
Since the low beam terminal will be grounded through the other headlight when the high beams are on, I think what you found is perfectly normal.
As mentioned, I think the problem is a high resistance connection. Try sliding the connector onto the bulb partway, and then checking for voltage directly on the bulb pins. I'll bet you find that the voltage "goes away" when the bulb is connected, indicating a bad connection somewhere up the line. And since it is affecting both beams, it's almost certainly the ground connection. You can double-check that, by measuring between the bulb pin and a good ground (like the battery negative post). As TOC suggests, running a new ground wire back to a solid ground point is an excellent idea.
Since the low beam terminal will be grounded through the other headlight when the high beams are on, I think what you found is perfectly normal.
As mentioned, I think the problem is a high resistance connection. Try sliding the connector onto the bulb partway, and then checking for voltage directly on the bulb pins. I'll bet you find that the voltage "goes away" when the bulb is connected, indicating a bad connection somewhere up the line. And since it is affecting both beams, it's almost certainly the ground connection. You can double-check that, by measuring between the bulb pin and a good ground (like the battery negative post). As TOC suggests, running a new ground wire back to a solid ground point is an excellent idea.
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Yes it is like you suggested Banjo. I can get voltage but no light. I hook up a test light like you suggested with the clip on positive and probed the socket and both the right and left turned the light on. I just saw your picture Randall, thanks much, I kinda thought the ground was good, but I will run a new one in the morning. Yes Randall I tried what you said and the voltage went away. In addition, this car is new to me and I cannot seem to even find the dimmer. I was thinking perhaps the dimmer is shorted. Moreover, could I have burned out the two new lights I bought hooking them up in a system like that? Does somebody know where the dimer is on a 71 super Beetle? I like a challenge, but not today.
Steve
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Nah, you wouldn't have burned them out.
It's been a while since I had to work on German stuff......where is the ground?
If I recall, some early ones grounded in the fender. Not good. Corrosion under fender bolts kills the ground. Ground wire needs to go through the wiring grommet into the nose, and ground there, NOT on paint.
It's been a while since I had to work on German stuff......where is the ground?
If I recall, some early ones grounded in the fender. Not good. Corrosion under fender bolts kills the ground. Ground wire needs to go through the wiring grommet into the nose, and ground there, NOT on paint.
The ground is inside the trunk through the inner fender. The part I am not sure about is the ground wirer does not come right of the light pig tail. It looks it goes into the harness about 6 inches and then doubles back out. Again it looks like somebody has had this apart because the connectors do not look right. I think I will have to open the harness some to be certain. I am still not sure about this dimmer deal. I will try and find a vw site and ask someone. However, in the past, I have tied that and nobody compares to the triumph people at the British Car Forum. I really mean that. When I was working on my daughters Lexus, it was Ben/Banjo who figured out my problem. I bought the books and they were questionable. At the end of the day, I was showing the well experienced guys at my favorite auto store what to do with the help of this forum.
Steve
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The doubled-back wire probably is an extension to get the ground into the body.
Whatever they used to connect the original to the extension is most likely where the issue is.
Cut the tape, and don't be surprised to find bare wire wrapped around the old ground lug, no solder, nothing.
If you had an ohmmeter, you could check continuity from trunk to socket.
Whatever they used to connect the original to the extension is most likely where the issue is.
Cut the tape, and don't be surprised to find bare wire wrapped around the old ground lug, no solder, nothing.
If you had an ohmmeter, you could check continuity from trunk to socket.
I unhooked the cover TOC and found the ground loop and redid the ground, but still no light. I need place to start on this thing. The PO turned this thing into a real challenge. They painted black undercoating all over the wires and removed and added some stuff. The dimmer is in the steering column at the blinker and does not work, so I am thinking of starting there, but I do not want to get in too far if I do not have too. I am thinking about something Randall said that it is a high resistance connection. Now do you mean a hot lead is grounding out or my ground wirer is poorly connected? I guess if a hot lead were touching the case it would blow a fuse? I am think I could unhook either low beam or high beam at the socket and just have a single system headlight and call it good. Is that possible?
Steve
Steve
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Head on over to "The Samba" for all your VW questions. To clean the undercoating off use some carb cleaner. You may want to hook up a temporary ground from the back of the pig tail to the head light housing. That wire that is doubling back may be the ground for the turn signal on the fender.
Well I finally got it; it turned out to be oxidation at the fuse box where the headlight wirer is attached. It was a real pain because it looked like the PO had added and removed some fog lights or something at some point, leaving a bunch of bullet connections. I did learn something’s like how the voltage reading will disappear under a load if there is enough resistance at a hot connection. I am glad you chimed in on that when you did Randall because I had that just happen and wondered what heck then I went in and read your note (put another star on that wizard cap). I am still not total sure how to use an ohm meter right, but I guess when I measured the white wirer and it showed resistance rather than 100% continuity, I was on the right track.
steve
steve