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Fri Sep 26, 2014 7:02 am

I have 1964 Vert and have always had issues with my head lights being dim. Several years ago I switched to 12volts and have never looked back. The only thing it did not fix was that the head lights did not getting brighter. I have been told by multiple people that it is something to do with the year and DOT rgulations and such on LUM levels but I am now calling bull on that. I recently replaced my Halogen sealed beams with the kind that you replace the bulb behind the light housing like new cars use. The light levels did not change. I have checked the voltage and found that it has 12.2 Volts running to it but I have no Idea what amperage should be and if it should be a higher voltage. They work perfectly and don't seem to have a short but maybe I am wrong.

High beams work great and are very bright.

Any idea why the beams are so dim? My wife thinks the "Velda' is imitating me :roll: .

Fri Sep 26, 2014 7:21 am

sounds like a ground issue. Are you measuring the voltage at the headlamp? Have you tried the lights directly off battery current? Check the voltage at all points, switch, relay. I had a truck here at work with that issue, bad ground at frame connection. Best of luck

Fri Sep 26, 2014 7:27 am

Check grounds. You may be getting 12V but without a good ground you aren't completing the circuit without loss; the resulting lower current means dim bulbs. Also check the low beam wiring all the way through the dip switch or relay.

Fri Sep 26, 2014 7:34 am

I will check the grounding and will also try the wire directly from the battery. While thinking about it I thought about the connections being old and may not be fully transfering power. Wouldn't that cause heat also?

Fri Sep 26, 2014 7:42 am

The same ground situation should be present on high or low beams. Agreed?

Unfortunately there is a lot of wiring to trace. Resistance might show up as heat.

I think I'd start by confirming that there is a voltage drop at the bulb, when under load. You need to compare high to low with a voltmeter, under load, at the bulb.

Fri Sep 26, 2014 7:45 am

I agree that the ground circuit is common to high and low Which would lead to
Corrosion on the contacts supplying the 12 volts to the bulb probably in the 3 wire connector on the back of the bulb....headlights wire direct with no breaks from the bottom of the fuse panel to the bulb connector.... follow your yellow and white wires

Clean the terminal ends by soaking in ....

Really !!

Fri Sep 26, 2014 8:36 am

Northof49 wrote: The same ground situation should be present on high or low beams. Agreed?

Yes, but. I've had buses where a low beam on one side was dim, high beam on the other side was dim. Dedicated grounds fixed the issue. VW's get wierd when grounds are there, but not very good

Fri Sep 26, 2014 9:23 pm

Make sure the ground and power wires are connected to the headlight plug in the right positions.

If they are in the wrong order you get the exact problem you are experiencing because low beam is grounding through the high beam power wire.

Sat Sep 27, 2014 4:06 am

Joel wrote: Make sure the ground and power wires are connected to the headlight plug in the right positions.

If they are in the wrong order you get the exact problem you are experiencing because low beam is grounding through the high beam power wire.

Not hijacking - but have the exact same problem on a 71 super - so you are saying the wiring at the pigtail is wrong? Let me throw on other thing into this - I disconnected the ground at one headlight and the low on the other side immediately got much brighter.....sound about right for this being the issue?

Sat Sep 27, 2014 4:22 am

It's a possibility,
If the ground wire is on the wrong spot the light will find a ground through whatever its plugged into.
That is why a bad ground can often make other lights come on.

Heres how they should be orientated.

Sat Sep 27, 2014 7:10 am

NOTE ; To change wires around in the 3 wire plug you have to slide a small pointed object into the black plastic clip to release the metal clip on the wire end

The new ends on my " new Wiring works harness " were so thin and cheaply made that I used the fifty year old ones that came with the car

Thu Jan 22, 2015 11:07 pm

I have been chasing high low beams not working properly since I bought my car 2 years ago. As mentioned here, when I could get them to work, the low beams were very dim. Usually they would not switch from high to low and back again, they would just get stuck on high beams.

I thought to myself that the PO put a new wiring harness in it and I figured it was miss-wired under the hood somewhere.

I just stumbled upon this thread tonight. I though it couldn't be as easy as the wires in the plug being in the wrong position.

Well I pulled my headlight buckets out, sure enough the ground and high beam wires were crossed.

I switched the wires per the diagram here and Holly crap....my lights works as they should! They even change back and forth from high to low without issue!

Thank you Samba Members for helping me solve my 2 year headlight problem!

Fri Jan 23, 2015 6:06 pm

tb03830 wrote: I have 1964 Vert and have always had issues with my head lights being dim. Several years ago I switched to 12volts and have never looked back. The only thing it did not fix was that the head lights did not getting brighter. I have been told by multiple people that it is something to do with the year and DOT rgulations and such on LUM levels but I am now calling bull on that. I recently replaced my Halogen sealed beams with the kind that you replace the bulb behind the light housing like new cars use. The light levels did not change. I have checked the voltage and found that it has 12.2 Volts running to it but I have no Idea what amperage should be and if it should be a higher voltage. They work perfectly and don't seem to have a short but maybe I am wrong.

High beams work great and are very bright.

Any idea why the beams are so dim? My wife thinks the "Velda' is imitating me :roll: .

Bro, I thought we were battle buddies and you didn't contact me. Oh well, no problem. Do you know how to perform a voltage drop test? Google it on youtube and you will see how beneficial it is. And remember this test "tests" the circuit under a load. So, saying that, if you have a basic DVOM, hook up the positive wire to your battery and your negative wire to the low beam wire on the backside of the headlight the DVOM will show you the "voltage drop". No math needed. Now this is the "total" voltage drop. There are a lot of things along this route that can contribute to a dim headlight, to include the ground circuit, which you can also perform the voltage drop on this circuit too. Just attach the positive from the DVOM to the ground wire on the headlite and the negative from the DVOM to body ground or the negative of the battery.
If I didn't word it right let me know and Ill re-write it, but once youuse it and see the advantage you will never have to question the validity of this test.
Hope this helps, HOORAH, Bill.

Fri Jan 23, 2015 7:05 pm

tb03830 wrote: I will check the grounding and will also try the wire directly from the battery. While thinking about it I thought about the connections being old and may not be fully transferring power. Wouldn't that cause heat also?

What you need to do is measure the voltage drop with the headlamps on. to do this, find a good body ground point, say inside the headlight bucket, (I assume the battery to body ground strap and battery terminals are good, as this problem you have only effect one of the headlight beams, not everything) A bad headlight ground strap at battery will effect BOTH high and low beams, as this electrical path is used for both beam levels

Now with a good ground on your volt meter negative probe on the car body, turn ON the headlights (make sure the bulb lights up) and measure the voltage at the bulb with the positive probe of your volt meter. do this by probing the headlight terminal on the back side of the headlamp, one of the three terminals will give you a volt reading, try each one till you get a volt reading for the dim bulb filament. If you got a dim light, the volt reading should be a good deal lower than battery voltage. Note the reading write it down

Now with the lamp still on .move the negative probe to the ground wire on the back of the bulb, it should be the Brown wire (brown is the standard VW ground wire color). Note the reading, if it is much less than the first reading, then you do have a poor ground at the headlight. try repair by removing brown wire, and cleaning contacts, shine up the sheet metal at ground screw in headlight bucket and repeat the test, see if voltage improved.

Now if the first and second test give similar voltage, then we know ground is good to the headlight, so the problem is in the positive side, the wire terminals, the fuse panel, the headlight switch etc....

With the headlight still on, measure the headlight fuse voltage drop, do this by (headlight ON, bulb installed) measuring the voltage drop across the fuse by finding a good body ground again for the negative probe, then with the positive probe test one at a time both the top and bottom of the headlamp fuse, the value should be close to battery voltage, and both voltages (top terminal to body ground and bottom terminal to body ground) should be about the same. If you find a huge difference between top and bottom fuse terminals (say more than a volt) then you got to much drop at the fuses, often the fuses corrode if so, replace them (recommend replace them all, they are cheap) also shine up the fuse contacts on the fuse panel and bend the contacts to give them more spring force on the fuses. If the fuse panel over heated (which can happen with corroded / dirty fuses, or loose fuse contacts), the contacts can get so hot they loose their spring tension, a new fuse panel would them be a good idea.
(note you can alternatively measure the voltage drop directly across the fuses top to bottom terminal of any given fuse (make sure what ever that fuse is protecting is turned ON). the bottom side of the fuse should get the positive probe, the negative side is the top (it don't really matter with modern digital meters, but does matter with the old style analog meters)
in this case you will get a direct reading of the drop across the fuse, ideally the drop should be zero, but in reality it may be a bit more, again the lamp must be on and it for this test to work.

next is to test the voltage drop across the high/low beam switch. there are tree wires on that switch on the firewall. One is from the dash switch, the other two go to the fuse panel, either for high or low beam. You can measure the drop across the switch by putting the positive meter probe on the input terminal (striped color wire, I think it is the center terminal) and place the negative probe on the each of the other two terminals one at a time, noting the voltage. this will be the voltage drop across the switch, one will likely give a funky reading (the one that is not on) grounding out thru the bulb, the other terminal should ideally be close to zero volts, if more than a volt or so, the switch may need attention,. clean the contacts, check wire ends to switch etc... or get a new switch if you switch to high beam, the other of the two terminals will give you the drop across the switch for high beam.

Finally test the dash switch in similar way, with light on, with positive probe touch the input terminal , it should have the fat red wire attached to it, then with the negative probe, measure the voltage drop across the switch by probing the medium diameter striped wire (this wire goes directly to the foot switch you probed earlier) If you got more than a volt or so drop here, you need to fix it too, however a drop on the dash switch will effect BOTH high and low beams, likely not the issue for you since you say high beam is fine. (however you may still find you can improve the voltage drop across the switch, which will make both high and low beams brighter)

Remember that measuring 12.2 volts you have reported at the headlight is good, however the light needs to on, bulb lit, else you are not drawing any current for your measurement. once current goes up thru a high resistance, voltage will drop across that resistance. so all these tests MUST be done with bulb on and lit.

also note that if you add up all the drops, the drop across the fuse, across the foot switch, etc... the sum of these drops is the total drop at the lamp!

If you find a drop of 1.5 volts across the fuse, drop 2 volts across the foot switch and drop of 1/2 volt across the dash switch, that adds up to 4 volts, which means your headlight will only see about 8 volts total (12-4=8!!!!)

My guess is that you will find a sizable drop across the foot switch and or the fuse panel, that would certainly cause the low beam to not get full voltage, yet may still allow full voltage to the high beam. the dash switch drop will effect BOTH high and low beams.

a lost volt here and lost volt there and soon it adds up, it don't take much drop to make a 12 volt lamp appear dim, loose a couple volts total and it gets dim a good deal. The voltage drops add up from each switch, fuse, terminal etc...

Good luck, post results please

Sun Jan 25, 2015 10:01 am

Any updates if OP fixed the problem?

Having wiring connected up properly really helps. Had same problem with a 1961 Beetle.

Even with the wiring connected up correctly you probably have loose and/or corrosion in your wiring connections causing a voltage drop. Take each connection apart for cleaning and dielectric grease. The grease will help keep future corrosion away for as long as possible.

Replace any suspect battery cables, especially ones with those replacement battery clamps that clamp onto the old cables!

Take off each battery cable at BOTH ends for a good cleaning and apply some dielectric grease. Do same with transaxle to body ground cable.

Soldering each connection in the fuse box really helps with voltage drops. If you have early bell shaped headlight switch solder internal/external connections in/on it.

http://www.thesamba.com/vw/forum/viewtopic.php?t=483901&highlight=fuse+box+soldering

http://www.type2.com/library/electris/vw-hauptlicht-schalter.html

Doing all of this gives you a faster/louder/brighter working electrical system that is safer for you and those around you on the road!

Replace any cheap aftermarket wiring terminals with factory style brass ones.

Crimping tool.

http://www.thesamba.com/vw/forum/viewtopic.php?t=338938&highlight=uninsulated+crimper

Sat Oct 29, 2016 3:31 pm

Hello all. I have had my first beetle, a 61 Turquoise ragtop, for a year, and have had dim low beams the whole time. I read this forum today, and sure enough, the wires were incorrectly connected to the pigtails. Changed the connections and now the low beams are at their proper brightness. Thanks for all of the great tips!

Sat Oct 29, 2016 4:17 pm

dmeffert wrote: Hello all. I have had my first beetle, a 61 Turquoise ragtop, for a year, and have had dim low beams the whole time. I read this forum today, and sure enough, the wires were incorrectly connected to the pigtails. Changed the connections and now the low beams are at their proper brightness. Thanks for all of the great tips!

Good to hear, but do not stop there. Get a multimeter and check for voltage at the battery and how much is getting thru the wiring.

Sat Nov 06, 2021 8:24 am

I know this is an old post but thought I'd add my $.02. I've chased dim headlights on many VWs over the years and the two that stand out in my mind were a '61 with both dim low & high beams. There was an issue in the headlight switch and a replacement cured the issue. The other was a '58 where only the low beams were dim. A new foot operated dimmer switch cured the issue.
*Of course in both cases all the grounds and connectors were cleaned beforehand as well as the headlight connectors checked for proper orientation.
Hope this helps someone