DeTomaso wiring problems are legendary and being inept electrically, my std fix is to simply grab a VOM and start chasing wires; when the volts stop, you found the problem (which cam literally be anywhere!) But you can try these age-old remedies:
1)- stock headlight switches literally fall apart inside causing problems. And I've seen cars with windshield water leaks in which some of the relays were full of rusty water!
2) the central ground under the dash can start all sorts of weird symptoms; remove the bundle of ground wires, wire-brush clean & reattach.
3)- the headlight grounds up front have been found to be too small in some xars or poorly attached in others. On some cars, the connectors to headlight bulbs were reversed!
4)- Erection problems can occur from a cracked grommet that supports and insulates one connection on the raise-lower motor (visible just in front of the lowe rad tank on drivers side). I removed the grommet entirely & used an in-line connector with a tie-wrap to attach & support the motor wire.
5)- the microswitches that limit travel to raise & lower corrode internally. They also disassemble & can be cleaned with Radio Shack Contact-Cleaner spray.
6)- sometimes the Emergenct flasher switch can cause weird problems, but before removing it (it comes out the front of the dash), make a color-coded map of where the wires on YOUR Pantera are connected. There are at least 5 different Factory Schematics and I've yet to find a car in which any schematic matched perfectly.
7)- finally, the European GBC fuses in our cars build a barrier layer of non-conducting oxide on the exposed aluminum fuse-conductors, and corrosion on the copper cups in the fuse holders themselves. A simple fix is to buy GBC fuses that are made with plaetd pointy-ends & glass envelopes (Busses Fuses back East make these). You'll need several little boxes to get enough of the sizes used by a Pantera.
All these suggestions assume a stock wiring system; if a previous owner or hack-shop dug around in there, all bets are off for everything except a VOM and lots of patience!
