What is the correct wire hookup for a hampton bay ceiling fan 4 wires.
The new switch has 1, 2, 3 and L

The same way your old switch was wired.

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)

This is not really mine but it is correct so I am posting it. Hope it helps.

For many four wire pullchains:

L - Black, 1 - Grey, 2 - Brown, 3 - Purple
L - Orange, 1 - Black, 2 - Yellow, 3 - Purple
L - Black, 1 - Grey, 2 - Brown, 3 - Green
L - Grey, 1 - Yellow, 2 - Purple, 3 - Black
L - White, 1- Black, 2 - Blue, 3 - Yellow