Hello Chris
There are various ways in which an AP will find its WLC. An AP that has registered with another WLC will keep that information stored, however, a factory reset should cause it to start searching for a local WLC. In any case, the best thing to do is to use the following documentation to see how to reset this configuration.
Once this is done, the best way to let an AP find the WLC is to use DHCP option 43 on the DHCP server to point the access point to the proper WLC. This is detailed below:
Try these out and let us know how you get along!
I hope this has been helpful!
Laz