Rescued a 72 Cutlass thats been sitting for over 6 years. Harness was balled up and sitting on top of the engine. I have the wiring diagram but am having a hard time finding some of these plugs. Can someone point in the right direction for these? Its an A/C car but the A/c has been removed. I know some of these may be for the compressor.

Also, what is the correct size bolt that holds the horn relay to the firewall? Cant find the correct threads.

 

The first photo is the feed for the optional underhood lamp. It is shown in the upper LH corner of the wiring diagram.
The second photo appears to be the wiring for the Transmission Controlled Spark solenoid, though I have to admit the pigtail that it's plugged into doesn't look familiar.
The third photo appears to be the connection to the A/C compressor clutch coil. The hardware store crimp connector isn't factory.
I don't know what's going on in the fourth photo. That appears to be the engine harness, but there should not be a purple wire in it. Trace that back to the firewall connector to see what it really leads to. The purple wire appears to be connected to the temp sender, but that should be dark green in the factory harness. There is no purple wire in the factory engine harness except the one that goes to the "S" terminal on the starter. Blue should be the oil pressure sender wire. The others should be the alternator wires (red, blue, and white). Clean them up so we can see the real colors. There should also be black, green, and pink going to the horn relay.
The horn relay screw is a sheet metal screw, not a machine screw with threads.

 

Thanks Joe. I will clean it up and get some better photos when I get a chance later in the week. Some of the wires were connected with wire nuts so wouldn't be surprised is there was some odd connectors.

The car was a mess when I got it but I am trying to get everything connected so I can test the engine and trans and also move it out my garage. I really just need ignition and starter, brake lights, transmission and alternator hooked up. In he meantime I can pull the fuses on everything else but trying to figure out the best way without frying anything. Nothing is plugged in on the engine bay side or behind the dash at the moment. It was all unplugged for paint by previous owner.

 

If you just want to start it and move it you can bypass the entire harness. Positive to starter, negative to engine block, alligator clips from positive to coil and momentary switch from positive to starter. A good battery can easily power it for a while without a charging system. For a short run 12v to the coil is acceptable.

 

I will most likely bypass the harness to get it moving but would there be a way to use the column ignition switch and key?

 

Yes, once you get the wiring sorted and connected in their respective positions.

 

Looks like a fun and challenging project! You'll be proud when you get it all sussed out.