I’m going to start this off by saying this is my first ever project car. I’m 18, and I’ve only had it for two weeks.

This is how I wired the sockets
Black to Black
Brown to Brown
Yellow/green to white


I thought I should mention I was told this wasn't normal, but on the two outside tail lights, the one on the driver side and the one on the passenger side, they have two wires, so I had to splice the two yellow to one white on the socket and then do the same thing with the green on the other side.

When I connect the battery, the two passenger-side tail lights turn on, but they are dim, and the two driver-side tail lights aren’t on. Then, when I turn on accessory mode, the two passenger-side tail lights get bright, and the two on the driver side are dim.

 

I just took a spare replacement socket I have in my stash and verified the wire colors that you used. They are correct. The sockets in your pic are wired correctly.

If the headlight switch is in the OFF position, nothing on the rear of the car should come on when you connect the battery. Same with the ignition switch: If the turn signal lever is centered-OFF, no exterior lighting should come on by turning the key. You likely have a ground wire problem affecting the circuits at the rear of the car.

You didn't indicate Coupe or Convertible. There is a ground point for all the black wires in the rear. In a Coupe the ground is below the RH cargo area light. Remove the halo trim to access.
In a Convertible the ground connection is behind the passenger seat, behind the carpet, about in the center. Look in the RH cargo cubby, you can see the black wire going through the hole to the front side of the panel, where it is secured with a screw.

There are connectors inside the car for the rear lamp harness. In a Convertible, this connector is at the rear of the compartment and subject to corrosion. In a Coupe the connector is forward, and isn't subject to corrosion damage like the Convertible.

Enjoy your project; enjoy the learning experience.

 

yes sir thank you, I'm going to check the ground wire now.
sorry for forgetting to add this but its a coupe

 

The Coupe ground connection is fussy to get to. Try something else first:

Rig a temporary ground wire from a clean bolt or bracket on the frame, or if you have a long enough wire, all the way to the battery (-) terminal. Connect the other end temporarily to any of the black wires at any tail light socket. If the rear lighting functions correctly with the temporary ground, find and check the interior ground for cleanliness and tightness.

 

hey so i changed the wires to:
Black to Black
Brown to White
Yellow/Green to Brown

let me know if you think i should change it back

So the problem I’m having is as soon as I connect my battery, my tail lights turn on, with the two on the driver side being dim and the third light on the passenger side also being dim , and then the one on the far side is bright, and when I turn on my accessory mode, they all have the same brightness. When I turn on my right blinker, the right tail lights turn off; the same thing happens with the other side. But my hazards work now, and then my brake lights also don’t work, which I was told they didn’t work when I bought the car, so I’m assuming it’s the brake light switch for that.