1999 Audi A4 power locks

1999 Audi A4 6 cyl All Wheel Drive Manual 92K miles
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I recently had to replace my car battery in my '99 Audi A4. I now have a new battery, however the power locks don't work? I am able to open the door manually with a key, however the remote won't open the doors. The door lock switch on the inside doesn't work either. Do the locks need to be re-set? re-programmed? My concern is because I am unable to open the gas tank door without using the keyless entry. any suggestions?

thanks