I'm trying to re wire a traffic light and I'm wondering how I get it to switch back and forth between the red green and yellow lights. I don't need them to go in order and I would like about 2 seconds between each light. Any help would be great thanks.:)

A timer device is what is used to make the lights switch on and off, and blink.

I have used this company many times, here is one of there catologs :

http://www.abb-control.com/timerscat/ss3-section.htm

A section on flasher devices as follows:

http://www.abb-control.com/timerscat/Sect6.pdf

There are many to chose from, you should have no problem finding what you need. Many of these parts are sold through Grainger.

Once you discover exactly what you need to make your project work ,I believe that Radio Shack may carry something in the same line.

If you have any more questions get back with them.