Hi Darren,
It is possible the battery is complete out and they need to be recharged. The sunlight in the winter is very week but that should improve in spring. Do you have an incandescent lamp, if so you can use it to charge the sensors for 3 days and they should be back to live.
Thanks,
Netro Support
Could you please send us email to support@netrohome.com with your Netro account registered email?
We will have our technician look into this issue.
Thanks
Regards,
Netro Support
I sent an email on the 4th to support@netrohome.com and have not even received an acknowledgment.
We have received your email and will send you a replacement unit.
Thanks,
Wency
Netro Support