Reverse light harness/reverse dash indicator?

[FSHTAIL]

So my cars reverse lights have never worked, I found this in the trunks lower sections of the side, but I don't see where it plugs into on the firewall exactly, can anyone help me out?

Also, if this goes together, will that mean that my dash reverse indicator light will work possibly? 

It's a 73 4 speed car if that helps any?
Thank you. 

[Bullitt-]

 this thread may answer your questions  https://forum.e-bodies.org/engine-transmission-and-rear-end/4/833-reverse-lights-wiring/1479/

[FSHTAIL]

I didn't see anywhere on the bulkhead connector that looked like it would plug into, once upon a Time the underhood was completely rattle canned black, including the bulkhead. 

I don't see where this plugs into underhood.   

[Bullitt-]

 would be the lower 4-on(3,4,7,8) the left if both your picture & this diagram are oriented the same

[FSHTAIL]

I don't see anything with opposing terminals on the bulk head in the engine compartment. 

[anlauto]

You're likely missing some sort of sub harness, or you have the wrong transmission harness...I'm not familiar enough with 73's to know for sure

[anlauto]

Here's what the typical 70-71 looks like and it's listed as 70-74    I don't see why they would change for 73-74

[FSHTAIL]

what does that plug look like that plugs into the bulkhead?

Here's what the typical 70-71 looks like and it's listed as 70-74    I don't see why they would change for 73-74

[anlauto]

It's the big white one in the middle, then you dash light plugs into the small grey one