I have a Hampton Bay Reddington II, remote control fan (no other switches) that works great when the switch cup is not attached. When the switch cup is attached, it makes quite a bit of noise. I've tried tightening screws, insulating the fan cup and moving the wires.. . Still very noisy. Without the switch cup, no noise. Noise is the same whether I use light kit switch cup or regular switch cup. Any ideas on what's causing noise or how to correct it?

You have to pinpoint exactly what is causing the rattle. Screws? Wires inside? Something touching moving parts? It sounds like you're already working on this. The good news is, you've narrowed it down to the switch housing without the light. My bet is on something making contact with moving parts when it's attached. Here's a bit more troubleshooting information if you want to delve deeper:

http://www.ceiling-fans-n-more.com/c...ng-and-FAQ.php