I have a Yale EF Kit 1 which has been working fine for about 3 years. I replaced the batteries recently (which I've done successfully in the past) but both my front and rear door magnetic contacts have stopped working (i.e. they don't trigger the alarm). Everything else in the system is working normally. I can arm\disarm with keypad and keyfob, and the PIRs trigger the siren when tripped. I've been through the learn and test procedures twice but the contacts still don't work. Any further checks I can do?