Clicking noise from fan timer switch

Don't think those were built to be repaired. Just replace it.

Not worth the time to even try and fix.

Sounds as a defect within the switch which typically is manufactured with a fuse inside. Hopefully it's just that one switch is defected vs a whole volume of them. I install the motion ones frequently as a design feature to my prospects. They love them! It is better to buy a new one and replace it.

If by chance the new gives the same problem, then the next step would be contacting the manufacturer. Also it's good to make sure there's not a overload on the voltage side(depending how long the device been installed to experiencing the problem). Even perhaps seeing if its grounded accordingly. Things to look at towards troubleshooting.

You would be amazed to know the little problems as improper grounding will cause!