Last night my orange brake light sensor came on dimly and intermittently, and then this morning my car wouldn't start. When I could get it to turn over, it would die after 3-5 seconds. I can't figure out how brake pad sensor and not turning over could possibly be related, but it's too much a coincidence for me not to ask, since it's only been 12 hours since the brake light first came on. Are there any possible problems that could cause both of these?

My friend asked about temperature, but it's been 3-6C every time I've started for the past week or so without a problem.