lightening87200

OK...this is driving me crazy. A while back I bought some red LEDs to replace the old yellowish dome light bulbs. And when I bought them I knew they would no longer fade like a bulb does cuz that's just how LEDs work. So now I'm thinking of doing some other lighting mods that I will post later but I want to know how I can keep my LEDs and fix the no dimming issue. I've heard I need a resister but I don't know what size and where I would put it. Any advice would be great.