Electrical

Tail lights malfunction

New to this forum… Issue: Toyota Corolla (1996ish)
—with headlights ‘off’ the park-to-drive brake switch works fine; but, when brake is depressed the dashlights and fog lights come on
—when headlights are ‘on’ the park-to-drive switch does not work (appears to be over-ridden) and brake lights are on all the time.

I figure there is an electrical short—but where to start looking?

Check/replace the brake light bulbs, and while your doing that, check the brake light sockets. Most likely it will be a bad bulb or bad socket, but the short could be elsewhere too.