I cant remember what year Pete changed a lot of the waring but you might want check in behind the speedo/tach panel for a cluster of relays. My 07 Pete has a 70amp relay behind that panel for the cab blower, like wise in the bunk there is also a 70amp relay for the bunk blower.I replaced the fuse for the Def fan slot but it didn't help. Then one at a time, I replaced every fuse in the panel in case it was a fuse that I didn't understand what the label said. I tried the blower with the key in the on position and nothing helped. I put back in the old fuses since the new ones didn't help. A lot of the labels was either hard to read or I didn't understand what they represented. But I tried the Def Fan first and nothing worked.