2004 Chevy Impala Door Lock Problem

2004 Chevy Impala

I have a 2004 Impala that had a lot of dead bateries lately and now the lock button switch does not seem to work properly anymore when I press the lock position. The switch works when I press the un-lock command. When I press the lock command, everything seen to work but the doors does not actually work. When I press the lock command on my FOB, I get the proper response (theft deternd is engaged, horn churps, etc) but the doors does not lock. Is there any feed back to this problem?

Thanks.

Denis