Is this the plug you have? If so this is how it should be wired, but ignore the wire color just incase they didn't use standard wiring color:

Time to bust out the test light and find out why you are getting power to the electric brakes. Double check that you don't have 12V and electric brakes switched or that the connections aren't shorted to each other. I have seen the set screws for the wires come out and short connections in the plug.