Yup they should light up, like you said...power (if it's getting power), LAN (if there is an active ethernet connection)..and the basic signal strength for the first steps of aiming to the other paired unit.
I take it they are not lighting up anymore? Does the unit still work...complete the link, pass traffic? Or...dead dead dead?
Old model, may have died by now...although we still have a few in production going on ....probably well over 10 years.