My 50+ year old farm tractor had no indicator lamp to indicate the ignition power is on. There is no key, just a push-pull switch. There is also no gas gauge, so I never know when it will run out of gas. It's no big deal to run out of gas. I just need to make sure I keep a 5 gallon can on hand. The problem is that when it runs out of gas, I often forget to shut off the ignition switch, and if that switch stays on for a few hours, the battery is dead.
I went to Radio Shack and bought a LED "pilot light" (has a built in resistor and an enclosure around it). It's made for 12 volt. (The tractor has a 12v battery). I installed it, and it worked great. Within a few weeks I noticed it would flicker, get dim, go back to normal, and so on. Eventually is just died, after only a few weeks of use. Yea, the wiring is fine. I intentionally chose a LED to avoid changing burned out bulbs.
Why would a LED burn out so quickly?
I should mention that the tractor has an alternator from a modern car, with built in regulator. These tractors originally had an old generator with eternal regulator, and were 6 volts. Almost everyone who still uses them have converted them to 12v, which is simply changing to a modern alternator, getting a 12v starter, changing 2 headlight bulbs, and putting a different resistor on the ignition coil. And of course using a 12v car battery.
Maybe this is just the result of buying crap from Radio Shack.... But I wonder if the vibration of the tractor or something else caused such a short life???