Or...
As Dream Land says, the engineers turn the fans 'OFF'...I've seen it the other way.
You have to remember, the wheel and brake temps continue to climb after the landing...with temperatures peaking maybe 25 to 30 minutes after landing.
As always, follow your company's SOP. But, the fans are optional equipment on the Bus...if you have them, use them. That's what they're there for.
PantLoad