Please Help! CD player problems! 1979 Deville

Ok, I have a 1979 Caddy Deville Coupe, and I recently attempted to install an aftermarket CD player in it, instead of the 8 track that was originally in it... Im 18, but I've installed all types of cd players and dvds in my previous cars without problems...(91 Caprice, 1986 Caddy Fleetwood Brougham, 1979 Ford Fairmount...) This time, I hooked the cd player up, that I had removed recently, from my 1986 Caddy Fleetwood, and hooked it up in the 79 caddy. I used an aftermarket harness, and that meant that I only had to splice two or three wires to hook it up to the aftermarket harness, and then plug the 3 plugs from the factory radio into the aftermarket harness... I snipped the wires that supply power to the factory radio, so that I could connect them to the harness. It came out to be 3 wires... 1 orange, and 2 blacks that are part of the same wire... I assumed that the constant wire was the orange one, so I hooked it up to the yellow power wire on the aftermarket harness, then I tried the cd player... The radio works fine, and the cd player powers on and everything... Then, when I switch the cd player to play a cd, a light under my dash comes on, and the cd won't play, and the cd player comes up with an error... But, I jiggled a few wires, and the light under the dash goes out, and the cd plays fine!!! I try to turn to the next song, and the light under my dash comes back on, and the cd player malfunctions again??? Keep in mind, that I didn't jiggle any of the wires attached to the cd player, I jiggled a wire attached to the car, that isn't connected to the cd player or to the aftermarket harness. I left the black wires unhooked, because I don't know where they would be hooked up to, or if they need to be at all. The only remaining wires that I had left to connect from the aftermarket harness is the blue one that you use to hook up an amplifier, and the illumination wire. The cd player I have doesn't have an illumination wire, so thats why I left that unhooked. The problem seems to be the light that comes on under my dash when I try to play a cd. Its not an led light or anything, its like a light that comes on when you open the door. The funny thing is, that light never comes on any other time! Please Help!!!!