What do these wires do?

[CmuCmu]

I was untangling the spaghetti yesterday at the engine bay and found some wires that I have no idea what they're for. The only issue I have currently is the headlights on the driver's side won't work, and the wipers have a separate switch (working on a single speed).
First couple of pictures show the wipers motor, and the wiring nearby. Have no clue whether those wires should lead to that motor or not. Red and black are for the switch I mentioned previously.
Third picture shows the plug where the washer fluid pump plugs into. Except, there are 2 of them (????)
Fourth picture shows the relays for the headlights, 4 relays, Bosch type, for 4 headlights. And the fuse carrier for a 30A. As mentioned, the issue here is, the driver's side pair won't work, and I have no idea how to test whether it's the relays or not.
Fifth picture shows some plugs, female, one with 2 and the other with 1 hole, that I have no idea what they're for. Also an ear that should (?) be a ground?
And the sixth and final picture shows an ear that's coming from the alternator (?). Engine is a 292, stock.

 

[Ricko1966]

The relays test for 12v on #87 in the socket. If you have 12v jump #87 to #30 on the socket side. That will bypass the relay. You should use a fused jumper to do this,but most people do not. If the headlights work then you need to check the relays apply power to #85 ground #86 resistance across #30 and #87 should be zero or very close. Post results,if we need to go further we will. The random wires under hood I don't have the bulkhead memorized but I'll do some digging and see what I can come up with. What are we working on? The wires with the red wire taped on I believe go to the wiper motor,Im guessing the park function doesnt work,so the switch is to stop the wipers,the wire with the rubber boot looks like oil pressure switch wire. Does this thing run?

 

[CmuCmu]

The relays test for 12v on #87 in the socket. If you have 12v jump #87 to #30 on the socket side. That will bypass the relay. You should use a fused jumper to do this,but most people do not. If the headlights work then you need to check the relays apply power to #85 ground #86 resistance across #30 and #87 should be zero or very close. Post results,if we need to go further we will. The random wires under hood I don't have the bulkhead memorized but I'll do some digging and see what I can come up with. What are we working on? The wires with the red wire taped on I believe go to the wiper motor,Im guessing the park function doesnt work,so the switch is to stop the wipers,the wire with the rubber boot looks like oil pressure switch wire. Does this thing run?

Thank you so much for the how-to on the relay testing, will update when I get to it later today. Also, thank you for whatever you can find on those odd wires.
As for the wiper motor, the wires (red-black) to the wiper motor go to a switch, just on/off at a single speed.
The wire with the rubber boot, yes, one of them is indeed the oil pressure switch, she currently has a bolt in its place since it was leaking and hasn't been replaced. (In my defense, I've only had her for a few days now and completely forgot my brother did that).
Also, she does run.
Edit: Added the sixth picture showing the odd plug coming from the alternator harness.

 

[75gmck25]

The 4th picture with the rubber boot and two wires looks like the A/C low pressure switch on my ‘75. The switch is mounted in the line to the evaporator, and that boot pulls off the switch quite easily.

 

[BadBowtie]

Big orange wire is not OEM. Must have been added for some accessory??

 

[CmuCmu]

The 4th picture with the rubber boot and two wires looks like the A/C low pressure switch on my ‘75. The switch is mounted in the line to the evaporator, and that boot pulls off the switch quite easily.

AC is currently not working due to low gas pressure, could it be this was disconnected so the compressor wouldn't engage?

Big orange wire is not OEM. Must have been added for some accessory??

Horn, couldn't figure out how to redo the iring for the steering wheel button to work

 

[CmuCmu]

Update on the headlights issue... Fuse blown.

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[DoubleDingo]

Update on the headlights issue... Fuse blown.

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Blown? Overheated!

 

[CmuCmu]

Blown? Overheated!

Got overhotted and then it blow, pwaffff
New fuse and weatherproofing, I got headlights now, yayyy

 

[Ricko1966]

Got overhotted and then it blow, pwaffff
New fuse and weatherproofing, I got headlights now, yayyy

A blown fuse is not just a blown fuse,it is a symptom of a bigger problem. Examine your headlight wiring carefully. No problem found rewire as stock. Then start over adding headlight relays if you want them. That way you will have a 100% tested and proven circuit( factory),and you will know any modifications to it and how they were done.