Alloy Metal Products Taillight Wiring Harness for 1965-1966 Mustang Coupes and Convertibles.
This taillight wiring harness is a direct replacement for your original harness. Connects back-up lights, taillights and the fuel tank sending unit lead to your underdash wiring harness.
It appears that the wire to the fuel tank now has a protective sleeve coating it. This would be more like the original harness instead of a single yellow wire with no protection.