I am having troubles locating an electrical.

Corroded slide-in ground terminals are common on the rear light sockets, but given the multitude of symptoms, I'd start by getting one of the rear lights to NOT turn on when it is supposed to, then troubleshooting that problem first. Expect to find a bad ground wire. One way to prove that is when you see some lights that are dim, unplug one bulb and the same one on the other side will go out.

Does your door switch look like this one? If so, there's an easy fix.

For future reference, they switched the format on this site and we aren't getting most of the automated e-mails telling us you posted a reply. I found your replies by accident.

You're right about the sockets being different. One is a two-wire for the backup light and one is a three wire for the tail light and the brake / signal light. Lets start with the backup lights. Pull out all of the rear bulbs except one backup bulb. That should be a two-wire socket with a single-filament bulb. Do you have the round brass base bulbs in back or the newer flat plastic bases? If they're round, that will be an 1156 or 2056 bulb.

As long as I'm here, this is a partial copy / paste reply for that switch when it is used on the sliding doors on the minivans, but the repair is the same:

The switch is a black plastic piece at the back of the door opening, half way up. Open the door all the way, then use a pliers to pop the switch out. It will only come out about an inch, then hit the door. Slide the door most of the way forward to make room to remove the switch from behind the door. Pull slowly because if the connector comes off and the wiring harness falls inside the body, you'll have to remove the seats and side trim panel to get it back out!

The switch is auto-adjusting. It is over-adjusted from slamming the door too hard one too many times. Pull the switch from the connector. Tie the harness into a knot so it won't fall inside the body. To reset the switch, you need to support the body of the switch on a hard surface with a hole in it that the push-button can slide through. A half inch diameter hole in a 2"x4" block of wood is perfect. Use a small hammer, a block of wood, or some similar object to hit the connector end of the switch. The rippled body will slide through the round mounting ring. It normally moves too hard to do this by hand. Now if you look at the push button end, you'll see it's sticking out about a half inch more from the ring than before. For a little added insurance against this happening again, I like to put a little gray Mopar RTV sealant around the ridges that are exposed now on the switch body. The gray stuff works best because it gets relatively hard compared to the black stuff. You can find this at the Dodge dealer's Parts Dept. Other types of caulk or silicone sealers should work too.

Plug the switch back into the connector and stick the switch back in the hole. You'll notice it pops in without much force. Once it's adjusted, the switch body will force the fingers on the mounting ring to expand. That's what holds it solidly in place. To adjust the switch, (now this is hard); close the door. The switch will slide through the mounting ring to its happy spot. When the RTV sealer sets up, that will help to hold it in adjustment. Slamming the door compresses the weather stripping and adjusts the switch. Then the weather stripping pushes the door back out against the latches. Slamming the door extra hard causes it to compress the weather stripping more than normal, and it pushes the switch in more than normal.

The 2057 is just a little brighter. Either one will work. For the single-filament bulb, check if that lines up with the clear backup light lens. If it does, that's the wrong socket. It should have a single terminal in the middle and a total of two wires. Someone put the wrong socket in there, probably due to the plug-in ground terminal being corroded off the old one. You might get it to work though. When people mistakenly put an 1156 in an 1157 socket, the bulb's contact bridges both terminals in the socket and causes all the brake and tail lights to turn on when any of them are turned on, so it would stand to reason the 1156 bulb will contact both terminals and work as long as either one is hooked up. Might confuse the next person though.