Okay when I had this problem before, it turned out to be the circuit breaker for the condenser blower motor. Same thing happens to me on the last leg of my trip between Amarillo and Houston.
So, I jump out and reset the breaker with the requisite screwdriver and walla, it starts back up and all is well. I attributed it to the rough road (remember the first time it tripped was when we went over the rumble bumps) so we motor along and in 30 or 40 minutes it does it again.
We reset it again and in an hour, same thing.
So I think either the breaker is weak or there is a possible high amp problem with the blower motor. Jon suggested maybe the brushes last time, but I can't figure why it ran well for 3500 miles then crapped out. I wouldn't doubt that I could fire it up today and run it for two days with nothing happening.
Has this happen to anyone else? I can't believe the breaker could just get tired and lay down like Lew, but hey that could be the deal. It is a 105 amp breaker, so who knows.