Left rear turn signal and brake light don't work?

I have a 1979 Bronco and am having issues with my left rear turn signal and brake light. When I bought the Bronco and first tried the left turn signal the green arrow on the dash just stayed green. Typically, this means a bad bulb, so I checked and replaced both the front and rear bulbs and still a solid green. Right signal works fine, but I changed the flasher anyways just because it was cheap. The front marker comes on when you signal but remains solid. No light in the rear.

I thought it may be a bad ground, so I grounded the rear socket to the chassis and still nothing. I bought a new rear socket because the other one was all crusty and that fixed the problem temporarily. About a month later it started to act up. It would work when I first start the vehicle but then after it got warm it would stop working again, both the brake and flasher. Sometimes, randomly, it will work.

I thought it may be the actual turn signal switch but since the light on the dash turns green I am assuming that is not the problem. If that was not making contact then it wouldn't turn the green indicator on nor the front turn signal.

Here is the oddest part though. I changed the socket on the left rear again just in case I got a lame one on the first exchange but that did not fix anything. I got out my voltage meter and put a brick on the brake pedal and lo and behold, I have 11v or so at the socket. I took the bulb out of the right side because it works fine and put it in the left but not even a flicker.

I took the brick off of the petal, turned on the ignition and turned on the left indicator and tested for volatage and I have 11v again but again, when I put the bulb in nothing happens.

All I can think now is that I have a bad connection or short somewhere that is allowing only a minute amperage through the circuit and as soon as that bulb is installed it shorts out.

Any other ideas? I really hate electrical....