Please Help! 02 suburban keyless entry

I would appreciate any suggestions anyone might have. Keyless entry (both FOBs)quit working about 3 months ago. Replaced the batteries - attempted to reprogram - changed the fuse - still nothing. When attempting to reprogram held lock and unlock buttons down but got no response (no cycling of locks, etc). Anyone have any ideas? Where on the vehicle does it receive the signal from the remote? That is the only place I can think to check but don't know where it is. Once again, any help would be appreciated.