Topic: 1967 Shelby Wiring

[kkupec02]

I have to get back to wiring and brake issues. I have Jim Osborn 1967 set of manuals including wiring. I also have 1967 service manual. I also have vacuum manual for 1967 Mustangs and Shelby's. Is there a separate manual for Shelby wiring? An example of why I ask is the tail lights that are different from Mustang. Each side harness has a green and a black wire going to the 3 light harness. Is one wire a ground because the housing is mounted into a fiberglass rear panel, or is one wire brakes/running lights and one wire a turn signal with the ground being on the gas filler support?

[Bossbill]

It works this way:
Brakes alone: Brake switch sends power to turn signal switch which divides power into left and right rear harness wires.

Brakes and right turn: Brake switch sends power to turn signal switch. Left brake power goes through switch.  Since right turn is indicated, brake power is interrupted on right wire. Instead power goes through flasher, then to idiot light and right wire.

Brakes and left turn: Brake switch sends power to turn signal switch. Right brake power goes through switch.  Since left turn is indicated, brake power is interrupted on left wire. Instead power goes through flasher, to idiot light and left wire.

Front turn signal lights also work in parallel to the turn signal wires above.

If no brake power and either side needs turn signal power, the above is also true. It's just that brake circuit is interrupted but no power was there.

So, in the rear you have 3 power wires. Brake and turn left; Brake and turn right; Running lights. The Shelby does have a ground wire.

[jwc66k]

It works this way:
Brakes alone: Brake switch sends power to turn signal switch which divides power into left and right rear harness wires.

Brakes and right turn: Brake switch sends power to turn signal switch. Left brake power goes through switch.  Since right turn is indicated, brake power is interrupted on right wire. Instead power goes through flasher, then to idiot light and right wire.

Brakes and left turn: Brake switch sends power to turn signal switch. Right brake power goes through switch.  Since left turn is indicated, brake power is interrupted on left wire. Instead power goes through flasher, to idiot light and left wire.

Front turn signal lights also work in parallel to the turn signal wires above.

If no brake power and either side needs turn signal power, the above is also true. It's just that brake circuit is interrupted but no power was there.

So, in the rear you have 3 power wires. Brake and turn left; Brake and turn right; Running lights. The Shelby does have a ground wire.

Sounds exactly like the circuit operations of my 65 and 66 Mustang GT Fastbacks, and my 99 E250, and my 06 F150. Jim

[Bossbill]

Since the Shelby does have the fiberglass panel I believe there is a  J-hook style connector that attaches to a left light stud and that wire goes to a internal-to-harness black ground wire toward the filler neck.
The right side also has one of the hook style connectors with a black wire which also goes toward the filler neck. The two grounds connect to each other with a round style connector at the filler neck.
Be careful as the main harness also has a black wire for turn or running (forget which offhand).
It may well be that you don't have the hook style as that may have been a PO or is Shelby era or style of light panel. Also, there are three different connector styles for early, middle and late cars that connect the Shelby harness to the Mustang harness.
There are also three different Shelby harness styles.
Without a car number -- can't help you there.

[kkupec02]

'So, in the rear you have 3 power wires. Brake and turn left; Brake and turn right; Running lights. The Shelby does have a ground wire."

My car is #817. At the tail light harness on each side, I only have 2 wires, black and green, going to the light assembly. The wires for the different functions must come together farther up the line towards the front of the car. Thanks for the help. I'll have to figure it out.

[Bob Gaines]

Given when your car 817 was built ,your Shelby tail light harness is most likely the type covered in a plastic tube. There is only the black and green wires in the Shelby tail light harness. The Shelby tail light harness stops/connects to the regular Mustang light harness at or near where the wires protrude from the loom for the regular Mustang tail lights. The wires were connected by way of butt connector to the regular Mustang harness at that point . What with the metal tail light boxes pop riveted to the metal remnants of the regular Mustang tail light panel structure and the tail light fixture /receptacle sandwiched between the tail light boxes with the all thread studs and nuts ,a precarious ground using the cars chassis is established. Although not technically needed the additional ground wire that is with the tail light wires exiting at the regular Mustang tail light harness loom is best attached to the Shelby tail light box or studs for a superior ground.