111jag

Hi,
I am assuming the way to wire the fog lamps is the same for multiple models of mustangs. The problem I have is I bought aftermarket fog lamps. I took the two wires coming from the car and wired one to the positive side of the fog lamp and the other one I attached to the ground of the car. I did this for both lights. I turned on my fog lamps and it began to burn somewhere in my engine. Not sure where. But when I disconnect one fog lamp and simple hook the ground from the lamp to the ground from the car (one of the two wires) the fog lamps work. (one fog lamp not attached to the car).
I have two questions. First do the lights have to be on for the fog lamps to work? I bought the car recently and the guy I bought them from said he remembers just driving with the fog lights on.
Secondly, is there a positive and negative wire associated with the two wires coming from the car for the fog lights and if there is how can I test to see which one is which?
Thirdly, can you solve my problem.