There are LEDs made especially to use with 12v and they will have a tiny resistor either built in the LED or in the wiring. An LED will have a + wire and a - wire. If you ground the - wire and touch the + wire to 12v + for just a bit you can tell. If it glows very brightly (too brightly) it isn't a 12v LED and if kept connected will burn out rapidly. If it is a 12v LED, it will glow at a nice even level. I used leds in the GPS and the programmable (pulse output) electronic speedometers I made for the AD. I used green for the directional indicators and red for the hi-beam. Good luck!
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
