1072 c10 Fleetside tail lights

[1972chevc10]

I just purchased a 72 chevy c10 and got it running and everything. The plug at the back of the truck on the frame wasn't long enough because it has a different bed on it from the original. I have a wiring diagram and made extensions for it and hooked it up. The headlights and front turn signals work fine but at the back, when the left turn signal is on, the right one flashes and same for the right signal. Also, when the tail lights should be on with the headlights on, the driver side reverse light is on only. I have quadruple checked the wires i made go to the correct place. No brake lights work at all. I did a little work with the test light and hooked up my extensions and got the tail lights working along with the passenger side brake light and both turn signals are correct. All of a sudden, the brake light i had working stopped working, and so did the normal tail lights. The turn signals sill work though. The dash lights stopped working at the same time. My wiring behind the dash is all original and it has a new headlight switch and turn signal switch. The brake light switch has 12 volts on 1 of the 2 wires. With the headlights on, there is no power at the tail lights. The rear lights only work with the blinkers. Any help? I have tried and cleaned all the ground so that shouldn't be the problem. The fuses are all new too.