What does it usually mean, brake fluid level seems to be fine. A little sqeak coming from the front, rear pads were changed recently.

 

My GS was doing that recently, only when it was cold outside and only when I was coming to a stop. Once I stopped, the light went out. Took it in and found it was low on fluid. Topped her off, and everything is fine now.

Jim

 

I suspect something related to the rear pad change. When that was done were the pistons pressed in and fluid forced back up through the system? Or was dirty or incompatible fluid used to top up the reservoir after the work was finished?

Anyway, this could be a little dirt floating around in your master cylinder causing the seals to leak. If the problem persists, I recommend a complete pressure flush and refill with high quality brake fluid. I use Valvoline Synthetic and it works great.

George