Possessed SUV Wiring?

[missyjord]

If anyone has any suggestions for my problem please post them, I've tried everything and searched everywhere with no luck!
91 Jimmy (VIN Z) 4.3L w/ AC
-No horn (fuses good, relay good)
-Tail lights STAY on with lights turned off, car turned off
-Turn signals only work on one side (fuses good, switch good) this problem only happens in unison with the tail lights staying on.
-Heater blower quit (relays and all replaced, blows fuses immediately, it is now directly wired to the battery and used with a toggle switch, seems to work well but overheats and melts wires.)
-Dash lights dim without touching the switch
-Dome lights quit (again fuses good)

All these problems seem to be related as when one happens the others do as well except in the case of the heater blower. Basically all I've been told so far is that my truck is possessed. lol Unfortunately that doesn't help much. As far as I've been able to figure is somewhere there must be a wiring problem, could it be in the fuse box? Is there anywhere I should begin my search? Taken the dash off and wires there seem to be in tact and normal. Oh and the stereo is direct wired to the battery too. Any help would be appreciated.
Thanks!

[MustangRoadRacer]

well, if fuses go out or a wire shorts, then the lights would go OUT.
however, because they are staying ON, this leads me to believe that there is a problem with your switch. Take out the lighting switch and check to see everything is in order.
In MOST (not all) cars, the headlights and interior lights are all controlled at the same switch.

the horn could go bad itself, try hooking it up directly to a power source and see if it works.

for the turn signal, check the FLASHER, and the bulb.
flasher is a cheap peice that (on my car) is located in the fuse panel. it controlls the delay of the bulb.
it is VERY cheap. so is the bulb.
good luck.

[bm2boats]

I've heard of this happening on Fords. Most likely is a loose Ground. Did anything happen to the car recently? Accident, Replaced anything, Added/ Upgraded anything( Radio, Lights, invertor, ...)? Probelms with the Trans?( I know it sounds stupid, But, believe me)....
If you bought this SUV in the recent past, get a Car Fax report.

[missyjord]

I've owned the truck for a couple years, no changes, accidents or anything. It's strange. I plan on replacing the switch soon as per the response from MustangRoadRacer, maybe that will help. If it's a loose or short ground, that could take a long while to trace down. Not looking forward to that prospect.
Do you know anything about fusible links?There appears to be one that was not factory (according to the wiring diagrams) that when disconnected fixes some but not all of the lights problems. Anything you can tell me about that? Thanks for all your help!

[MustangRoadRacer]

The traditional fusible link is a short section of wire that has a smaller diameter than the rest of the circuit. When current flow in the circuit exceeds that of the fusible link, the wire melts and interrupts the circuit.
When it blows it must be replaced. It's a pain, and old technology.