What size cord do i need to hook my satellite radio up to my after market cd player?

its hard to explain but i bought a cord from radioshack since the one that came with sirius did not work with my after market cd player. it has a yellow and a red that i plug into the cords in the back of my player and connects the sirius with a single. It works but it is making my car door speakers cut in and out. i found that when i wiggle the cord connected to my sirius that it will come back on. I suspect that this cord is possibly to big. Anyone have any ideas of what i can do? If this is not clear enough to understand i can try to better explain it. maybe?