Sure. Put 12V on the fan harness pin B, the white wire.
Unless the coolant temp is above 220-230 degrees, you won't be able to feel much engagement by trying to stop it with a rag along the edge.
Without the exact code, without parts store interpretation, it's difficult to tell you more. But assuming you've seen other threads for troubleshooting that involve the sensor schematic, you might have a sensor side problem, not a fan engagement problem. Still could be a flaky harness. A close physical inspection is in order.
You have a voltmeter and know how to use it?