05' Accord Spoiler Light

Hello,

I installed a spoiler on my car and when I first installed it, the light did not come one and I later found out that I put the wires on in reverse and blew a fuse. Some of the wiring even melted. I corrected the problem and it was working correctly. Then yesterday, I bought a splitter for the cigarette light plug so that I can plug in a radar detector and a cell hone at the same time. As I was backing out of the lot, I noticed that the spoiler light was not on. I had just plugged the splitter in the socket before I started the car up. I checked and the wires were melted again and were still very warm to the touch. This time, the fuse was not blown.

The spoiler is new and it had not rain heavily until the last couple of days. Do you think water got into the light? Is there a car electrical problem with the splitter? Did the splitter short the light? Can I get some type of wire fuse to prevent this from happening since I keep losing wire every time this happens?

Thanks