Headlight Meltdown . . .

[SheStang87]

I have been having major problems with the headlights of my '87 Mustang. At first it would start to get a little warm up where the switch is on the dash. Then it melted down the back of the switch where the plug goes. So I replaced the switch, and it happened again. So I made a bypass switch from a toggle switch(like the kind from switch panels) and the same thing would happen!!! She melted the electrical tape off and burnt up the connectors, so I replaced that again and checked over the wiring, but it still happens. Is there such a thing as some type of sensor some where in the dash that may have gone bad and caused this? Does anyone have any idea what may be causing all these problems? I thought that maybe I might have a short some where but wouldn't a fuse blow? I'm in desparate need of information, so I would greatly appreciate any theories or opinions.
Thanks alot!
Christina