Brake light question
 

The brake light on my 1997 f150 has come on. Anyone have any ideas what it may be? The brakes have always felt like a sponge until you go half way down to the floor with them, so I don't think that has anything to do with it. Brake fluid is full and the brakes are in ok shape.(meaning there is about 35% to 40% left on the front and back) Any ideas what made the light come on?

It is either low fluid in master cylinder (low brake pad thickness or leak) or the emergency brake switch ahs ,malfunctioned or the emergency brake pedal is slightly depressed. If brakes are spongy there is either air in the system or a rubber hose has a weak spot and is bulging.

Checked the fluid 3 times and it is full. I think the pads will need replaced soon and I am gonna check the hoses. The Ebrake seems fine. I am gonna bleed them as soon as I can.