problem with turn signal when apply breaks

I have a 93 corolla and have a problem with my left turn signal. When I apply the break peddle, either running or off, my left turn signal comes on a dull solid (not blinking). It is similar to when you have your hazards on and apply the breaks, both stop blinking and they go a dull continuous lit. Where would I start to troubleshoot this problem. Any help you could provide would be great as taking something like this to a mechanic will be a costly and time consuming ordeal.