Farmall Cub

Radec Aksarben wrote:. . . I disconnected the reds completely from power at one point and they still fluttered when the engine ran! . . .

Do they still do that if disconnected from the flasher?

Yes. They were not connected to anything but air. I don't know what in the world... Brand new wires...

Not sure how helpful these pictures are.
The amp meter and headlight switch is in the normal box.

The switch (no relay) and flasher are in the top rusty box.

The flasher has a ground wire that is grounded and threaded to the top box. There are 2 prongs on it. One marked L for the output and the other is X for fused power. There is a 20 amp spade fuse on the hot side of the in/out light switch that powers the flasher. There is also a glass 20 amp fuse on the switch. The L wire off the flasher splits to each of the 2 amber flashers.

The second picture was actually taken before the 1st when the reds were also powered off the IN/OUT switch. They were removed for the 1st picture below.

Then I'm back to my original comment, except the RF is acting directly on the LEDs rather than (or as well as) the flasher. Take one of your lights and hold it close to the distributor while it is running. It will probably really go nuts. You can use one of the lights to find where the interference is worst and thus identify the source. Then you can attempt to remedy it. You might be able to fix it by changing to the dreaded resistance spark plug wires.

You might try putting a light inside a metal box to test whether that would reduce or eliminate the problem.

These lights are grounded through the mount screw. Maybe I could ground them with a wire and hold them by the alternator just for fun as you suggest.

They are sitting within a 5 sided 1/4" steel box now in my fender extensions



Might come down to trying to find an incandescent light that small too.

What do you mean by "dreaded resistance plug wires" wiring is not my thing. I'm embarrassed to not know what you are talking about. I just go to stores and ask for plug wires for the application when I replace them.

The original plug wires on older engines, including all older tractors, had a solid copper wire to carry the electricity to the spark plugs. More modern equipment, starting with cars and trucks, has plug wires with a built-in resistance. This change was made to reduce the radio frequency interference coming from the ignition system. It is typically done by making the core out of some material that is an imperfect conductor. For an ignition system to work properly with resistance wires, the rest of the ignition system needs to be designed accordingly. If resistance wires are substituted for solid wires, it often causes engine operation problems. Since cars and trucks have used resistance wires for 60 years or so, people accidentally make the change to resistance wires when they go to a parts store and end up buying generic plug wires.

You could also try taking off your alternator belt and testing your flasher/lights. If they work normally, your problem is related to noise from the alternator. If the problem still happens, your problem is probably from the ignition system.

I don't have a better reason as to what specifically was causing the issue other than what has previously been discussed but it is now resolved.

I bought incandescent versions of the flashers and a new flasher (still the bimetallic type) that works with variable load. Tada! All is well.