I hadn't been able to use the garage door keypad since I moved in. This past summer, I decided two years was long enough! After inspecting it, I realized the a battery had been left in and the connector was corroded. So, I headed to Home Depot and bought a package of 9-volt connectors.
Once back home, I spliced the wires together, programmed the keypad, then held my breath ... and it worked! It's amazing how something so small and trivial can make life so much easier.