Here are the under dash wiring harnesses.

The main wiring harness used on 1968 Shelbys is Ford part number C8ZZ-14410-D.

Things you should know:

Ford used four different 1968 underdash wiring harnesses depending on how the car was built. Various ID numbers were used to identify this harness.

This harness is a "Tach" harness. It matches both the instrument gauge harness and the headlight harness. Some functions, such as the rear window defroster, are not used on Shelbys.

All 1968 Shelbys had tachometers. If you are upgrading to a tach, this is the correct harness. The tach wires are an integral part of this harness.

Some of these wires extend into the engine bay. Make sure all of your plugs will work together. In some cases, new plugs will not plug into old plugs.

There is a yellow three way plug on the harness, near the fuse block. It provides constant power to accessories. The red three plug is part of the lighting circuit and only provides power when the headlights are on.

The fog light harness is an auxillary harness. It was only added to cars with the fog light option. It is Ford part number C8ZZ-15A211-A.

Things you should know:

All 1968 Shelbys used this harness. You can add fog lights to a non-fog light car. This harness connects to a circuit breaker, the switch and a power source.

The air conditioning harness is also an auxillary. It was added only to cars equipped with ac. It is Ford part number C8ZZ-19945-A.

Things you should know:

The ac harness is unique to 1968s and not interchangeable.

The instrument harness fits behind the gauge pod. It is Ford part number C8ZZ-10B942-B.

Things you should know:

This harness is different from the standard Mustang harness. The configuration of the light bulbs and circuits is unique to a GT/Tach car.

The tilt harness was added to all cars with tilt steering. It is also an auxillary harness. It is Ford part number C8ZZ-3D568-B.

Things you should know:

This harness has an inline fuse. It connects the door switch to the underdash tilt mechanisms. It actually plugs between the headlight harness and the main harness. This harness is unique to the 1968s.