Sometimes it would seem Volvo's safety features become dangerously redundant. Case in point - that very convenient bulb sensor, if it fails as mine did, will kill the brake light circuit and not show any indication that all brake lights are out. I recently discovered that I'd been driving without brake lights for close to 1,700 miles. The only thing that clued me in to the failure was my cruise control suspiciously failing. Since I just had the car inspected before the failure, I was not in my usual "check all the lights visually just in case" mode - admittedly my bad. Since I don't use cruise control that much, I obviously did not catch the problem right away. It seems ridiculous that the absence of a luxury option would be the only clue (besides being rear-ended) that brake lights are not working! What about cars without cruise?

Anyway, I consider it my duty to get this info out there for those who might want to double-check these things. And thanks to the info in the FAQ, which shows the link between these two circuits - without it, I would still be oblivious, and probably in an at-fault accident by this time.

Drive safely everyone!