Magneto headlight problem

[Oldav8tor]

I converted my headlights to use a 12 volt LED bulbs wired in parallel. I chose bulbs that work with the original BA15 sockets. The left one works great - the right one flashes on and off with no rhyme or reason. I've:
1.) Swapped bulbs
2.) Changed plug-in sockets
3.) Ran a separate wire from the + on the plug-in socket to a independent 12 volt source
4.) Cleaned contacts as best I could
5.) Checked wiring for continuity

I have not disassembled the headlight other than removing the bezel and lens.

The only thing left is the lamp socket in the headlight itself... you wouldn't think something so simple would cause trouble. I wonder if anyone has had a similar problem and what the solution was?

[Les Schubert]

Just a guess. The T magneto puts out AC. Perhaps a problem for one of the bulbs?

[Novice]

Tim. Check Your ground connection to the headlight can. Try wiggling the headlight can and see if that effects the headlight. I have a connection problem with the 6 volt LED headlights flickering and going on. off. and dim. on My 23 express. the headlight mounting rod that goes through the fender to the frame is a little loose causing the Headlight to flicker. Might take a seperate ground wire to the headlight to fix it if You cant get a good ground from the frame to the headlight mounting rod.

[Allan]

It is standard practice for my auto elec. son to solder wire from the bulb holder to the headlight body, usually at one of the rivet heads, to give a positive earth. Relying on the sliding contact between the socket and lamp body is not the best.

Hope this helps,
Allan from down under.

[Piewagon]

I recently changed the headlights on my 1915 Roadster to run them on a 6V battery. I used 6V bulbs which in fact need a better ground than LED's. Try the simple things first like I did since my problem was a bad ground from the bulb case to the frame. Since the car has a starter added the frame ground was good because there was no need for any additional battery cable straps to make the starter spin fast even at 6V. Here is what I did:

Notice that there are several items in series mechanically and electrically from the headlight socket to the frame. The headlight bucket is riveted to the headlight arm bracket. The headlight arm is fastened to the fender iron arm via a threaded connection. The fender iron arm is attached to the frame via a threaded connection. A bad electrical connection at any one of those points can and will cause the problem you are having. Do the following:

Remove the cotter pin and nut at the bottom of the headlight bucket arm. This is the nut that fastens the headlight bucket arm to the fender iron. That usually is a 1/2" diameter fastener. You need to go to the hardware store and buy an "INTERNAL TOOTH lockwasher" that just fits that threaded stud. DO NOT use a split type lockwasher since they don't "bite" into both the nut and the fender iron. External type lockwasher also don't bite where the metal is smoother and likely to give you the good connection you need. Before you head to the hardware store - remove the nut on the bottom bolt where the fender iron is fastened to the frame and buy an internal tooth lockwasher for that connection too. It is a smaller diameter than the headlight arm and you need the correct diameter washer for each place. That will make sure the fender iron is bonded to the frame bolt nut. Both of these washers will bite into both upper and lower surfaces and typically the threads will bite into each other. You "might" also have to put one of those washers under the head of the bolt that fastens the bottom of that fender iron in place but I was able to make a good ground just with the one easy to install washer on the outside. Make sure both threaded fastener nuts are tight and cotter pinned. This should result in a good ground at the headlight bucket.

[Mark Nunn]

Tim, I have worked closely with a few of LED manufacturers over the years. The good ones include over-voltage protection in the lamps. The circuitry will temporarily turn off the current to protect the diodes. For example, if a 24V power supply was connected to a 12V LED, the light will flash. The frequency of flashing is in proportion to voltage. You could check this by measuring the voltage at the bulb or swap bulbs and see if the flashing moves to the other headlight.

[Oldav8tor]

Ok - first to clarify a few things. I'm running the LED Headlights from a 12 volt battery-not magneto. The left headlight is fine, the right flickers. No change if I swap bulbs. I'm using the two contact type connectors.

I apparently misunderstood how the bulbs are wired internally. I thought one contact was hot the other ground so I wired the sockets accordingly. After reading some comments to my post, I went out today and disconnected the ground - to my surprise, the light still worked. Touching the disconnected wire back to ground had no effect on the bulb. I also tried connecting the former "ground" terminal to +12 volts - no change there either.

Needless to say, I'm a bit confused. Seems strange that applying + or - to the other terminal has no effect. I didn't get to test it tonight for "flicker" but will do so tomorrow. I will also remove the reflector and examine the socket - possibly soldering a ground wire to it as Allan suggested.

Thanks for your help!

[TRDxB2]

Some LED bulbs are + - insensitive. LED flickering is usually associated with a voltage fluctuations - loose wire or circuit drain. So have you checked the voltage at the base of each light while on? Since they are connected in parallel is the one farthest from the source the one flickering? Might help to know who's bulbs / model you bought ?

[Novice]

Tim. Some replacement LEDs have one pin positive the other negative with no connection to the case. Your 1917 touring had the original Headlights wired in series for use with the magneto. The car didn't have a on.off.dim position Headlight switch like the 1919 to 1927 cars did. only one brightness level. If You have a 12 volt power source. deer feeder battery ect. You can test the bulb connections outside of the car to see how it needs to be wired up. a lot easier that way. You can wire the lights for just one brightness level or add a SPDT switch for ON.Off.Dim.

Good Luck.

"It's the little bugs that eat Your lunch"

[Oldav8tor]

Here's the latest - I replaced the socket in the headlight - I couldn't see anything obvious wrong with the old one but I can't see what's going on between the contacts because they're encased in a rubber cylinder. I also cleaned the mounting shaft on the headlight and the receptacle in the frame to insure a good ground. No flicker now and I credit the new socket as I had checked everything else before changing it. I also went with new bulbs given me by Tony Osentowski, a local Model T Guru. They work a lot better than the ones I bought. It is a single contact bulb but Tony soldered a brass washer around the contact so it connects to both pins in the headlight socket. I've connected 12 volts to one of the pins leaving the other open and it works fine. My 1917 has a simple push-pull headlight switch and I'm feeding individual wires to each headlight from a post on the terminal strip that is attached to the switched pole of the switch.