When you start getting really oddball things going on there I'd be looking at the grounds....... ........I've found that when turning something on makes something go off that shouldn't.

Maxwell a little more information please. Do the T/S blink, not light up, light up but not blink? What number flashers did you use? When you say that pressing on the brake turns off the light on the opposite side I would think they must be lighting up but I am not sure. Also when doing all test on T/S or brake lights please have the tail lamps turned on also as that will show up bad grounds. What is your battery voltage at the flashers? How are the bulbs and sockets and what bulbs did you use? Make sure the bases are clean and the ground wires where they connect to the body are clean. Get us some more information and should be able to get you going again. Also you might mention what year and model your working on. The wiring was basically all the same but it might help to know what you are working on.

 What year is your Pinto

Just the way most cars are wired, lack of a proper ground is more often than not the problem.  Whenever I have a car that has a ground that uses a "springed clipping" action (as most do) I scratch the socket and solder a wire to it.  I then use a connector, screw, and anti oxidant compound to the body for more secure connection.

In most cases you have the resistive action of the bulb to the socket, the socket to the housing, the housing to the body and the body to the negative battery terminal. There is a lot of opportunity for a diminished or complete loss of ground.

In the case on my Sunbeam's Lucas system (aka: The Lord of Darkness) I'll be soldering a wire to the socket and running the wire directly to the battery's negative terminal.

Tom