[the roadie]

Most certainly the fan clutch, but just unplug the harness going to it to confirm it's not the relay. If it stays on high speed, it's bad. Pre-2005 were the ones prone to early failure.

Lots of threads about changing them.

 

[the roadie]

Dorman (a good aftermarket supplier) makes them and they've been seen for $110-120 on Amazon and Ebay. Rockauto has them for $132.

 

[the roadie]

Relays hardly ever fail, but you have a point. Swap 45 and 46 - they're the only two identical ones in the front fuse block. The other one is for low beam headlights and the DRL function.