Unusual 2000 Malibu problem

Today, after driving about an hour, I went to turn on the heater and nothing happened. That is, the fan would not turn on, regardless of speed setting, the fresh air vent / recirc settings did not light up, the ac would not turn on, etc. All other dash items seemed to work ok. While the power locks worked, I soon discovered, as I was pulling up to the bank drive-thru, that the power windows did not work, either from the driver door or passenger door. As I was pressing all the buttons for the windows and window lockout switch, suddenly I heard the fan kick on and then everything worked !! The windows worked, could turn on the ac, vent selector worked, etc. Originally, I thought I blew a fuse or two but ruled that out when things began to work. Any idea what caused this? The washer fluid light was on along with the red engine symbol on the bottom right of the cluster. Thanks, and all suggestions are appreciated.