There’s are a few easy things you can do to test them first…
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Disconnect the fan at it’s plug. Apply 12v power directly to the wires (one negative, one positive) and see if the fan works. If it does, and it spins freely, and without wobble, it’s probably OK.
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Check the fusebox under the hood. You should be able to locate the relay for the fan using the diagram. Find another relay with the same part number on it, but that works something you can live without (even the A/C for this purpose) and swap them. Run it up to temp, being careful not to overheat it and see if the fan comes on. Heck, you can even try the circuit you switched it with to see if that component is running. Might be quicker.
The coolant temp sensor is a bit harder to test, but it should short when the coolant reaches the set temp, whatever that is. You can test this right after testing the relay. You’ll want the engine hot, just past the point where the fan would normally come on. Just get your multimeter (set on ohms) on the probes and see if they pass electricity. If they do, then the sensor is OK.
Replacing the fan is just a mechanical swap. The amount of things you have to remove to get at it may not be that simple, but I’ve never swapped an Ion fan, so I can’t direct you there.
Relay is beyond simple. Pull and push in.
Sensor will require the radiator to be drained. If there’s no drain plug, you’ll have to remove the bottom hose and let it drain.
Someone may have more ideas, or slight alterations to the above, but that’s the basic way to go about it.
Good luck,
Chase