TheSamba.com :: View topic - 1969 Beetle: Headlight Wiring Headscratcher

Sat Jun 19, 2021 3:47 pm

Hello All,

I have a '69 Beetle, which for some time, has had a very dim drivers' side headlight, while the other headlight was fine. In replacing the bulbs, we found a similar issue with the new bulbs. Driver side dim, passenger side fine. Then the drivers' side just stopped working (we plugged the old bulb back in and it too, had quit working, indicating a wiring or fuse issue).

We checked the fuses, numbers 5 and 6. Fuse number 5 is the fuse to which the wire running to the drivers' side headlight is plugged in. Using a tester, we find:

-->There is power at the fuses inside the car.
-->Inside the trunk, there is power to fuse 6, but NO power to fuse 5, at the block.
-->A controlled test is done to switch the wires running to 5 and 6, and not surprisingly, the passenger headlight does not work while the drivers side does.

Is it possible that within the block, the plug to which the wire that runs to the drivers' side headlight (from fuse 5) is malfunctioning, while all other plugs on the block seem to work?

If there were a problem with the dimmer relay, wouldn't both numbers 5 and 6 be malfunctioning?

Has anyone encountered anything similar?

Sat Jun 19, 2021 5:12 pm

The fuse holders like to get corroded and/or lose their tension. Pull the fuses out, clean the ends of the fuses, take some sandpaper or scotch brite to he terminals in the fuse block, then ever so gently bend the terminals to tighten around the fuse better. Then recheck.

Sat Jun 19, 2021 8:02 pm

And once you have done all that, check for any earth wires near the headlights. Remove the fitting, clean with sandpaper until shining, clean paint to bare metal underneath the screw and terminal, dab with some dielectric grease and tighten back up.

You can all the supply voltage that you can but if the earth is poor, you won't light your bulbs properly.

Sun Jun 20, 2021 9:59 am

the power going to the fuses is common (brass strip connection between the two) , so there should be no way for the power to not be going TO both fuses, unless there is something very wrong with your fuse block. The fact that you switched the wires and the problem changed sides says there is nothing wrong at the headlight.
I am assuming you mean there is no voltage coming to the other side of the fuse, in which case it's probably corrosion or a bad fuse.

BTW< I have a 69 sitting in my driveway and I just looked at the fuse block and the wiring diagram

EDIT: It may be possible that the connection between the wire tabs and the fuse tabs is bad. I honestly have never had to look that deep, so I do not know if it's two pieces or one at that point. A voltmeter will tell you a lot

Sun Jun 20, 2021 3:04 pm

Dim headlights?
Make sure the ground wire on the sealed beam is on the correct tab.
Looking at the back side of the sealed beam you should see...
Yellow, low beam, is the top tab.
White, hi beam, is the right tab.
Brown, ground, is the left tab.
The headlight will work with the ground on the wrong tab but it will be dim. Like a DRL.

Wed Jun 30, 2021 10:50 am

To all who posted tips and advice, thank you. I lightly sanded the terminals, checked the ground wire, etc., as suggested. The headlights work! These were excellent interim tips for me while I await a new fuse block to install. I appreciate all of you!