Pop you hood. to the left of your battery there is a fuse box. Open the fuse box. On the side closest to the battery, remove the first fuse labeled "20". That is the fuse for the stereo and radio on a 2004 nissan maxima.
There are two fuses for your 2004 Nissan Pathfinder radio. There is an in-line fuse behind the radio. There is a fuse in the fuse box. The fuse box fuse will be in the second column, fifth from the bottom.