I have a 2GIG system installed with 2 2GIG-TS1 keypad. The problem I have is the LED button won’t light up on one of the keypad unless it is arming (stay red while arming and turn OFF when armed). No green LED our white LED. they will light briefly (white and green for a few seconds) while I reset it holding the 2 buttons. I only have this problem with one of the 2GIG-TS1 keypad. What could be the problem?