I have 1992 300TE. When I first start up the car, the defroster, heater and A/C with fans work fine. After it runs for 2-3 minutes and I have turned off the fans and I try to turn the fans back on, no result. I am guessing it is a fuse. When I checked the fuses, I didn't see one burned thru? From the fuse box legend, #7 runs the fans, but it looks fine.