I need a wiring scheme to attach a new pull chain switch to four wire fan assembly. The colors are black, gray purple, blue. Instructions don't help.

An addendum to this: The Part is labeled with L, 1,2,3. What position does each wire go to.

You can contact Hampton via this link. https://www.askmehelpdesk.com/electrical-lighting/ceiling-fan-troubleshooting-repair-frequently-asked-questions-46738.html Ask for new installation brochure or wiring diagram.

How was the old switch connected?

Ceiling fan pull chain replacement and repair - Ceiling Fans N More (http://www.ceiling-fans-n-more.com/ceiling-fan-pullchain-replacement-and-repair.php)