This could be a result of many factors but the most common ones are:
1. Dead batteries - keypads run on batteries and have no indication when it is running low or need to be changed.
2. Damaged wires - wires can be worn out as a result of different weather conditions, causing the connection between wires and keys to be interrupted
3. Stuck keys - dust and dirt can accumulate in between the keys. Clean the inside and outside of the keypad with a clean cloth, paying attention to the spaces in between the buttons.
4. Old keypad - keypads are located on the outside of the home and can be affected by different weather conditions throughout the years
5. Malfunctioning code - depending on the model, after batteries are replaced, the keypad may not recognize the code. To reprogram the code, press the learn button, leave it for a few seconds then input the new code. If this doesn’t work, check the manual instructions or call an expert.