Toyota Repair: brake light warning on dash, toyota avalon xls, toyota avalon

Question
I have a 2002 Toyota Avalon XLS with 73,000 miles and the brake light warning indicator on the dash stays on.  Initially the indicator light came on and no lights were out.  The indicator light went out on its on about a week later.  Several months later the indicator light on dash is back on.  The upper brake light was out.  The bulb has been replaced and the light is now working but the indicator light on dash won't go out.  However, I have noticed when I turn the key on but don't start the car, the indicator light on the dash doesn't show up but if I touch the brake petal, the light comes on again.  Is there a sensor in the brake petal?  Any way to fix without taking the car to the dealer?  Thanks.

Answer
there are a couple of common trouble areas although it's usually a bulb problem so make sure the bulbs are all checked, if any bulbs show any discoloration at all replace them, check the bulb sockets for any bad contacts and make sure the white/black ground wires are connected tight. There is a light failure relay in the trunk under the carpeting of the left inner fender, it's attached from behind to a metal bracket, these have been known to burn out causing these sort of problems.