I had this happen for a while in my car too. There is a small reset switch somewhere on the radio that you can depress with a pin or paperclip. Holding that in (I honestly can't remember if it's just press it, hold it for 5 sec, or hold it for 10/20sec) will show that it is resetting and that it may take a few minutes. When mine was messing it up did this my whole trip (about 10 minutes or so) and when I got back in it was all good. You may want to try this first as it is a bit easier than looking for fuses or messing with wiring.