Hoping for some advice and please note I am not an electrician I am just trying to troubleshoot a problem before calling one.

I have two pairs of ax130 tn sensors operating lights in an outdoor domestic setting.

My question is when I take the covers of the sensors what should I see as far as led lights are concerned. I have a sensor that has no light on it unless the beam is broken, it then turns red.

The other sensors seem to have either a permanent red or green light on. Which is correct and can you suggest a way to troubleshoot the sensors to find out if I have a faulty one?

Thank you in advance.

Best thing to do is post photos of the transmitters and recievers

The red light shows the device is activating, there will be a set of alarm contacts. these maybe C NO NC or just C and NC depending on age. This will only be on the recievers. Use a multimeter to confirm the contacts are changing states correctly