So i replaced my license plate bulbs with white led's from superbrightleds a couple of months ago because personally I think the car looks sooo much better. They worked great until a couple weeks ago when they started looking like strobe lights. They flash really fast except with no real pattern. Now the weird thing is that when I half turn the key, only the electronics not the engine, they don't flash but as soon as the cars running they do. And making me more confused is the fact that when i put a halogen in one side to compare it didnt flash or dim at all at any time....so whats going on here?

 

My guess (WAG at that) is your alternator is starting to go bad. Really, just a guess though.

 

The power is certainly getting shorted somewhere. LEDs are either on or off there's no dimming but the halogen should dim if thats the issue. I guess if its fast enough to not dim it then it makes sense.

 

resistors on the positive feed to the socket usually does the trick for LEDs. Something about the voltage requires them. Im sure someone will chime in