Fuse or Other?

[imagesinthewind]

This morning I started the 81 and noticed the aux gauges for the WVO (level and temp) weren't working but I just figured the wires must have come off at the tank.
When I got in to take the kids to school (8AM, 25*) I pushed the defrost button and nothing. Nothing at all. I figured the fuse for that part of the console broke. With no time to check or fix I told the DH and took the gass guzzling yukon to work. He took the 81.
He called me just after 8 and said when he slammed the door after getting in, the gauges lit up and the defrost came on.

Any ideas what may have happened???
Thanks!