Fan clutch?

[JimT]

Started the day at home with my engine fan stuck in high gear. Hooked up Insite, fan wasn't supposed to be running. Checked the air supply and switch. There's air going to the fan and the switch appears to work properly.

So, before I run off to buy parts and start tearing stuff apart, anything else I should be doing/checking? Also, does the radiator/coolers need to be moved or is there another way to work on it without moving them?

I personally washed the truck last night. Brush and garden hose. Gently sprayed down the engine, could that have affected the fan? It was near the end of the day and this morning things were still a bit damp.

Anyway, any input would be appreciated.

Oh, maybe a stupid question, but is it safe to drive the truck around with the fan constantly on? I'm supposed to be picking up a load for delivery tomorrow. 400mi round trip total distance. My initial thought is no, cancel the load and fix, but what say you folk?