It is easy DIY

If you means the warning light on instrument panel, it is easy to fix it yourself.

Use a screw driver to loosen 2 or 3 screws on the intrument panel. then the panel can be taken off, you can see a curcit board. disconnect a wire connector, the board is free now. the brake warning light is a tiny bulb. buy a replacement bulb, put in on, and put everything back. If you have the bulb on hand, the whole process takes about 15 minutes. I have replaced a turn signal bulb this way.