Its easy, I changed out the ugly green bulbs and replaced them with red bulbs and they look great when on.

Just unscrew the two screws and pull out the cluster, then you will see 3 black things, pull them out and just head down to autozone and buy the bulbs. They cost about 3 bux and you have to buy two packs of two. Best thing they sell every color (green, red, blue, etc...)