'73 to '71-'72 wiring harness compatibility

I picked up a 'tested good' wiring harness from one of our friends almost 2 years ago, hoping to have a 'good' harness to put back in my car. It turns out that the '71-'72 wiring harness that I got from Joe (Mach 1 Club.com owner) is actually a '73 harness. I know this now because of what should be 'sport lamp' sockets have a third wire, and there are no 3-wire plugs for the valance-mounted signal lights.

My question: is a '71-'72 "engine compartment side" of the harness compatible with the '73 "passenger compartment side" of the harness? (I'm thinking at the point where the inside plugs into the outside via the beige screw-down plug that joins the two together)

If not, I might have a 'good' [and almost totally clean] '73 harness for sale.

well there are a few differences as far as the wire coloring, but it also depends on what accessories your car had verse how the 73 was equipped.

the harness is different as you have noticed for the sport lights, but the main connector should be the same back at the top of the fuse box.

the 73 differs more in the dash area as far as accessory plugs, on the 71 even if a car didn't come with underdash lighting the connectors were present on the harness.

however this started to change in 72 when they started having these Daughter harnesses that would plug into the main harness and augment it

then for 73 they started installing just the harness the car needed and didn't leave room for expansion later.

so for 73 you need to make sure you match your accessories to the harness, for 72 its similar but you can get away with some things.

mach 1 is special for 72 and 73 so you want to start with that if you have a mach 1, but the signal lights are different, so you may have to cut from your hold harness to splice into the new one to match the connection points.

I took a wrecked 72 mach 1 harness and mixed it together with a 73 convertible harness just to make one good one for my mach 1.

the wire coloring and banding was different for 40% of the 73 harness, but the main connectors were the same(except turn signals).

I also had wrecked 72 sport light connectors, so i had to take apart the 73 sockets rip out the extra wire and connector then splice it back together with my 72 wiring.

the difference i found out with the 73 socket verse the 72 socket is the 73 is Deeper then the 72 so when i put the lights into the socket and installed them into the sport lamps, the bulb sat much further back in the lens then before.