You should just be able to hear the jet engine take off while driving, meaning your fan is engauged. Most mornings my fan will run until I hit about 30mph. When it's on you can hear it running.

There are people that test a clutch fan with cardboard, engine hot, shut off, hold cardboard in fan, start engine still hot, cuts cardboard clutch is good but my thoughts are if you can't hear it, it's bad or you need hearing aids.