Rough Morning With No Heat in the Car

It sure was a rough drive today.  My heat cut out again for a bit.  It had done it about a month ago for a day, then came back.  So I paid it no mind.  But it happened again, on the worst day for it.  No visibility, windows freezing up, etc.  But I made it to work, so all is well I guess.  And the heat came back on when I got close to work.