Hello; I haven't seen this answered yet elsewhere, so I thought I'd try.
I have an 87 Formula that has been Hillbilly over-ridden/rigged with wires & such. Last week, I was driving at night & I heard a pop & my dash lights & tail lights went out.
I've found a number of no-no's that have been done to the car & I've fixed loose & bare ends, etc. & I still can't find the short. It seems to be in the headlight switch assembly. When you turn the lights on, the lights flip up & then blow a fuse, & you can turn the headlights off, but the hideaway lamps stay up & won't retract. I then no longer have taillights or dash-gauge lights. If you put a new fuse in the dash light slot of the fuse block, it will spark a bit. It will bring the headlamps back down, but if you leave the fuse in, it will blow after about 2-3 sec. I can't find any more loose grounds, or bare wires, or anything.
Also, if you remove the light switch, you can put the fuse in the slot & it will stay without blowing. If you plug the headlight switch back in to the connector in the dash, it will blow. It's almost like there's a hot lead somewhere that shouldn't be live or something. I took the light switch apart & all seems ok- no loose terminals or contacts, & contacts are operating in proper sequence.
I'm out of ideas. Please help!!!!!!!

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LowBuck87Formula

 

I had most of the problems you have. First of all, I replaced the headlight switch and found a broken wire on the connector. It was one of the paired wires, I soldered it together. Next, I had a bulb with a broken base in one of the taillights and replaced it. Then I found bare wires for the horn and side marker light on the front driver's side fender, they were rubbing on the sharp body part. I replaced the bad wire and put a plastic wire loom over the wiring to protect it from future wear, no problems now!