Brake lights stay on when headlights are on in 98 mercury villiager. Why

Are you SURE it's the brake lights, not the tail lights? Does the 3rd high-mount light stay on?

Hey... Yes the 3rd high mount stays on as well.

Being an electrical engineer, this is driving me crazy. Either the computer module, or a tail light wire is shorted to a brake light wire somewhere in the wiring, or at the bulb socket. I own a '98. Look and see if the front parking lights come on when you hit the brake pedal, with everything off, that will tell that story.

Good info Trippmeister. I suspect the socket, juice leaking over from the contacts. Dana, try replacing the bulbs and while they are out spray some contact cleaner, copious amounts, in the sockets. Repeatedly. If you see green or white corrosion, that is evidence of the power jumping from one contact to the other