This is starting to sound like an issue with the wiring going to the rear lights themselves. Possibly a bad ground.

Does this vehicle have wiring for a trailer? If it does then the trailer wiring is where I'd look first. Bad trailer wiring is usually the number one cause of exterior light issues.
Also, underneath the car at the very back there should be a wire that comes out of the harness and grounds to the frame of the truck. There should be one on each side of the vehicle.

If one or both of these connections are corroded or no longer connected at all it would cause your issue. I would check these first before sending it into a garage for service.

 

I am the 2nd owner of this truck. Its a 1998 Chevy Blazer. Do trailer harnesses come standard with these. I have never seen a harness anywhere. Could it be hiding up under the back somewhere?

So I am looking for a grounding issue it seems? Where would I begin issue. By grounding issue I assume you mean a bare wire is touching the metal frame somewhere? It seems just to be the Passenger Rear light that is giving me this problem. The other lights are working fine.

 

You can get them from the factory both with and without a hitch and wiring installed as an option. If you have a trailer hitch then you probably have a trailer wiring harness as well.

As for the grounding issue. All electric circuits require both a positive and a negative in order to work. All modern american cars run a negative ground system. Meaning that the negative side of the circuit runs through the body/frame of the vehicle and the positive side runs through most of the wires through the truck. Meaning that you could have an issue with a disconnected ground wire OR a positive wire shorting out to the frame.

So the negative side of your lights will be connected to the frame. Under the truck behind the rear tires, on each side there should be a wiring harness that runs towards the back bumper area.

There is a single wire as seen in the pictures below that should be grounded to the frame. This is the wire that most often gets corroded or rusts off completely and gets detached from the vehicle causing light issues. And should be checked first as an easy fix before going to a repair shop.

 

Ok so I noticed fuse blew after brake was pushed. I looked down on the dash under the floor mat and saw they attached wire coming out from the way. I pull it up and it just came out. Hardley pulled at it. I looked on the wire and it says "Turn Feed -> 10". Its a grey wire.

Is this my problem?

I attached the best pick I could take with my camera phone. It looks like one end was cut someone, not sure. The other end looks like it went to something. Could this finally be it?

 

That is odd... How long is it?

 

Its not even a foot long. But the one end I can see was definitely cut. The other end looks that I believe went to the fuse panel. When I pick it up to look at it, it just came out of the wall behind the brake pedal. I had a ignition switch put in about a year ago and I had an aftermarket remote start that was messing with the security pass lock feature, so when they put in the new ignition switch I told them not to reconnect the remote start.

 

Sounds like wiring left over from that install. Factory wiring does not have notes on it to allude to its function.

 

Ok so we checked voltage on the wires. Somehow the parking light wire to that right taillight is getting pratically no voltage. Tried to trace the wires and they ran up into the ceiling. So we finally just jumped the right parking light to the left and we have lift off. Turn signal is fine as well as brake light. Crossing fingers again. Turn signal and Brake light both getting correct voltage as the left.

Hope I have found a solution.

 

It sounds as though you have essentially bypassed a bad negative ground. As long as all your lights are working properly and you used the same gauge wire then there should be no problems with your solution.