Its a Fan controller issue. I had this in my Sedan.
Take out the glove box and behind it on the heater control piping is off colored plastic peice with a wire plug going into, It will be facing up towards to top of the dash. Un-hook the plug and remove the screws to take it out. You will see some of the wires are all messed up. Replace it with one from the junkyard. I did this When I was replacing some trim that required me to remove my dash. That might be necessary to replace it, at least make it alot easier.
Good luck.
