98 taurus sho brake lights

the brake lights will only come on when you push the brake pedal to the floor. what would cause this?

Sounds like a bad, or sticky brake switch.

The brake light switch will be located at the brake pedal arm. There will likely be two switches, one for the brake lights and one for the cruise control/vehicle speed control. Do you know if the brake lights were ever working with light pedal application? If not, maybe the switch is working but needs to be adjusted.

-Rod