Brake light problem

[94Droptop]

So I bought one of those ebay tail lights and when I hit the brake its not working. some time is flashes real quick, sometimes nothing, and some times it comes on and goes off. Whats the problem. The turn signals work fine. Its not like i spliced wires together it actually came with a plug. Could the switch be bad. When I bought the bike the brake lever was busted off from being wrecked. Thanks guys.

[Miller'sR6]

It could be a bad switch did you replace the whole master or just the lever?

[94Droptop]

I only replaced the lever. The master cylinder didnt appear to be damaged and is working fine except the switch part.