Bruce Mills

I have a 1997 Boxster, the brake lights are on when my foot isn't on the break and then go out when I put my foot on break pedal.

So basically the reverse to what should happen.

Any suggestions?

extanker

might be as simple as a brake light switch or [rare] a weird back feed issue

Bruce Mills

I thought switch, but then thought maybe relay?

Is there a Relay on brake lights?

Macster

I believe you hit upon the cause I too believe it is a back feed issue. Corrosion some place is letting current flow the wrong way. Not lots of current just enough to light the bulbs.

But where this corrosion is I have no idea.

Qmulus

Check the wiring at the pedal switch. That is about the only place that you could have an issue that would cause that symptom.

There is a normally closed terminal (labelled 4) with two black/red wires, a normally open terminal (2) with a black/orange wire and the connection for power (1) with a solid black wire. It is possible that the black/red and black/orange wires were swapped at one time, or perhaps the switch is bad.

whalebird

Sometimes people will force a bulb into a socket (double filament) where the side lugs are offset....backwards. The double contacts at the bottom of the bulb crosses the contacts in the socket creating a feedback. Can't remember if boxsters use dual filament bulbs, but the rear fog light might be a place to look. Check all bulbs for proper fit and location.