Sometime the brake lights on my S90 work, sometimes they don't. It doesn't matter how hard I push on the pedal. Sometimes if I slam my foot on the pedal, they come on and work but other times they don't. Sometimes just lightly pressing them works, sometimes not. I saw on here in an old post that it could either be the microswitch for the brake lights, or the bulb failure relay. I can't quite get to the switch yet, I still need to remove even more parts of the dash. But where is the bulb failure relay on this car? Is it the rectangular relay on the left hand side of the trunk? Or somewhere else? Because I don't see a "red cylinder relay" anywhere.

Thanks in advance, and any quick answers are appreciated.

Steven