Turn signal fuse keeps blowing

My friend has a 95 GT and whenever he puts his car in reverse (it is a manual) the turn signal fuse blows. He has tried replacing it a couple times, and it blows only when it is put in reverse.

It probally is a short somewhere, but has anyone had a problem like this. Also where is the reverse switch in this car.

the reverse switch is connected to the side of the transmission by the speedo cable, you might want to try pulling the reverse light bulbs out,put it in reverse and see if there is a short to ground in the wires if the fuse blows you need to find the short and repair it or if you can't find it run new wires.