Celica Forums General Discussion Exterior Holy crap!Need Help...almost had an electrical fire!

Okay, the celi's fine don't worry, but I definately got the shit scared out of me. Soooo, yeasterday I decided to take out the neon footwells and put leds in their place. Well I already had a switch prewired for the neons so I just hooked up the leds to that...well the wire to the led started smoking and the ground wire started to spark and It shocked me but it didnt hurt so I started to just rip all the wires out really fast. Anyways long story short I have a bunch of melted wires. Now did this happen because I was using the wrong gauge wire? Or, is there too much power from the cig lighter? Any help would be greatly appreciated.

First off what kind of LEDs did you use ?

I bought these leds from autozone...unfortunately I left them at home so I dont know what they are called (im at work) but they were like 7 bucks for a pair. It is two single leds each with there own power and ground wire attached to them.

Ok so you bought LED lights that were already ready for hookup ... good

It sounds you had a short in the line, the positive and negative wires are touching each other with no load to power, ummm ... I'd say it was probably the LEDs you got. If everything was fine before this happened then you probably got defective product.

If you can rewire your Neons to double-check and make sure everything works on that switch.

Also did you originally have that circuit fused ??? because causing a dead short, should have blown a fuse unless you were taking power directly from the battery. Which isn't a very good idea.

I don't think it blew the fuse because my cigarette lighter still works???

strange, LED needs smaller power than neon.
you connect the neon directly to the battery using some relay or not?

I had the neon connected to the cigarette lighter fuse for the power.

Did you have an add-a-circuit on the cig lighter fuse? or did you just wrap a wire around the fuse end(s)? If you wired a fuse around both ends of the fuse, THERE'S your problem, since even a blown fuse would allow power to the neon wire...

on time i had the APC strut bar on my car. it had a clearance problem with the battery terminals. One night after class i got in my car to leave and it wouldn't crank over... no power at all. so i popped the hood and i saw that the pos terminal was knocking against the damn strut bar burning a tiny hole on it and I had to put the terminal back on very carefully without tools. phew

Neon lights need high voltage AC to operate. To get that from a car's 12V DC, it goes through a oscillator, then is stepped up by a transformer. (so really, it could be rippling DC) LEDs want ~4V DC. So you'd want to put a resistor in series to divide the voltage across it.
So if you didn't have the kind of neon tube with the transformer built in to the plastic casing and you had a LED across AC, that could be bad.