Where can the harness be purchased reasonably priced?

Best is a salvage yard.

If you havethe time and a voltage meter with Aligator clips,

I have removed wiring harnasses then

1. Disconnect battery

Wire brush male connections.

2. Trime a nail file to fit in female slots and clean with file

3. Connect Resistance meter (I prefer those that sound off when a connection is present) to both ends of wire,

follow each wire inspecting for cracks in insulations or worn areas, bend stretch and twist as you run the length of the wire. If the sound from the meter stops or needle moves. you found the bad wire or break in the wire.

I then replace the entire wire some just remove the bad area and splice wire together.

For splicing,

Cut and trim wire,

slide electrical shring wrap (one inch each side of splice length)on wire away from bare wire,

press wire together

Twist

If in car cover area around wire with aluminum foil

Flux the bare wires

solder with a conventional soldering iron and leaded solder

slide electrical shrink wrap over the bare wires,

heat to seal

It is only time and this process is easy when done on a junk yard harnass then when complete, install in the car.

I mark the wires with a paint pen when they check out ok.

Be systematic and careful and when don slide a cabel sheath over harnass