E46 M3 will not crank, start

ok, since the temperature has gotten cold, the car won't crank. all dummy lights come on, radio is fine. had battery and alternator tested at autozone. all tested GOOD.
when the car will actually crank, it fires up just fine, like a full charge. no hesitation at all. this is an intermittent problem, and i cannot find a pattern to it.

i am thinking a bad fuse? which should i check? is there a starter fuse, an ignition fuse, an immobilizer fuse? any other fuses to check? anything else to check? any recommended procedures? car is 6MT

thanks