Recently put in a new headlight switch on my '72 Roadster. Now I've found that: 1.) when the lights are on and I apply the brakes, the right rear taillight goes out completely and 2.) the horn and the wipers no longer work.  Anyone have a clue what's going on here? Thanks. 

why did you replace the switch..you are talking about the high low switch or the one that turns on the lights..remove the bulb on the right rear and see if the problem goes away or changes..does it do the same thing with the turn signals on right turn flash..try to isolate it..I will dig my manual out of my car and see what is all hooked together..
Rich

Can't see anything with the headlight switch that would effect the horn or the wipers. The rr tail-light going out when you mash the brakes is most likely a bad ground in that socket.
The wipers could have been taken off-line when you pulled the dash cluster forward/off to replace the light switch. There is a small solenoid on the back of the tach/speedo cluster for the wiper door...that may have gotten disconnected by accident. Other than that, there's no real correlation.

Are you saying the horn & wipers work until you turn the headlights on?

Okay...it appears the right tail is not as bright as the left even when it's just the lights on. Replaced the bulb, but nothing changes. Right turn signal works, but is also dimmer than the left turn signal. That's with the lights off. With the lights on, the right turn signals do not work at all. When I remove the bulb, and turn the lights on, the turn signal works (in front, of course). When I removed the bulb I also tested the horn and wipers, but neither works.