I installed me some blue led bulbs in the dome lite after the fades off the led blue is still barely on..very very dim does not go completely off my car is a 06 mustang gt.

 

Moving to tech..

It would seem strange that a bulb would stay on even though nothing else (the switch) was changed. Is it possible that maybe the light just has a glow that fades after a while?

 

What's is the forward voltage of the LED...they will light up at minimal current.

 

It's something having to do with the smart junction box, as I was told a couple years ago when I installed my LED's. I guess it doesn't completely cut off power like a switch does but instead leaves a trickle going to the plug, and with an LED that's enough to light it up slightly. I dunno.

 

I switched my dome/map lights to LED also from diode dynamics. Have had them for close to 6 months. Even when off they have the faintest of glows. I remember reading that it has something to do with the fact that the led uses such little power that even a small trickle that gets through allows it to glow. Another bulb like an incandescent for example takes a lot more power. And the trickle wouldn't be enough for it to glow at all. Basically, LEDs r really efficient

 

I have LED Reverse Lights. Same thing happens to me. Either they are really cheap or, like mentioned above, really efficient. I could dust of my EE coursework to find out but I don't want to know that much

 

u saw pretty much my extent as an ME student lol

 

Mine does the same. Overtime, the light will go out completely. Nothing to be concerned about.