problems with auto focus on canon eos 3

the auto focus only works on the top two rows of focus points any body got any ideas?

They have a lot of focus settings in the CF functions. I just set mine to the center and leave it at that. Sometimes the battery gave me grief but I just went for the battery holder and loaded XX eneloop AA and never had a reoccurring problem. Keep going through the settings of the functions which you probably have but small adjustments can cause problems. Lens problem ?