2004 is relatively old if these haven't been maintained. In my previous rig, I had to work on my Fantastic Fans every five years or so. Tweak the fan rings and the shroud so that they weren't rubbing, spray a little contact cleaner into the cover sensor so it would release properly, same for the thermostat and directional switches, etc. Have you done all that stuff? Have you ensured that power is available at the power switch (central fuse issue)?
2019 Cougar 26RBSWE
2019 Ford F-250