If there are 2 sockets in your housing you can covert one to dual filament and use it for tail and brake and the other for signal. The only problem with that is you'll have a bright bulb and a flashing bulb in the same lens. The flash may be hard to detect.
If you are determined to use the same housing for all you need to get a 7 wire switch and wire it right.
Have you seen my
tech tip?
