My '87 740 did this - turned out to be a corroded (dirty) connection on the brake light socket - a little (very) light sanding and application of electrical cleaner cleared it up, but only for a while. With yours being only a couple of years old, I don't know if that could be it, but might be worth a look - does one of the brake lights appear dimmer? That was what led me to look at that particular socket...
Another key - it ONLY did it with the lights on. You probably have day time running lights (?), but try it with the headlights on versus off and see if it does it one way or the other - could be looking at a marginal bulb or (dirty) socket.
|