i dont know if it's been covered before, but I found an easy way to fix taillight problems on my 70 Camaro. While I was getting my car road worthy, i yanked the harness and traced every single wire with a meter (I couldn't afford a new harness). It took a long time. One area I couldn't get consistent results on were the grounds for the tail lamp sockets. I thought I was doing myself a favor by cutting out the old sockets and soldering in new napa brand sockets (they look the same as the ones painless sells). Well, I was driving the other night and someone pulls up next to me and tells me my rear lights aren't working. I go home and sure enough the lights are out. I wiggle the wire harness and the lights start to work, but with the lights on and the left blinker on, the right taillight goes out. When it's on, it's dim. I let go and they stop working. So I knew it was by the socket. When I pulled the socket out and moved the wires, I noticed the ground wire wiggled easily when it should have been solid inside the socket. So I decided to yank a little harder and it came right out. Apparently, the ground connector is a folded over piece of tin and slips up in there during factory assembly to join with the main metal frame of the socket. Must be for assembly line ease. The problem is the tin is annealed and too weak to hold tension against the frame when inserted in the hole. When looking up in the hole, I could see black charring on the plastic from the connection getting hot from the bad contact. What I did was cut the tin connector off and used a 3/16 wide female crimp on quick disconnects (radio shack# 6403132) to slip onto the tang inside of the hole. It worked perfectly! You can buy them from radio shack and other places. Make sure you get the red ones that are for 18-22 awg wire otherwise it will slip off after you crimp. You might also have to stick a screwdriver down the hole of the light socket to move the tang a little more to the center of the hole so you can slip the connector on. It should only cost a couple bucks and beats buying a brand new harness!