KMC Controls BAC-8007 Installation Guide - Manual (Page 74)

Bulbs are open If one or both bulbs are open—as tested with an ohm
meter—it indicates the voltage or current on the network exceeded safe
levels. Correct the conditions and replace the bulbs.
Bulbs not inserted correctly One lead from one or both of the bulbs are not
inserted into the socket.
Section 8: System integration and networking SimplyVAV
74 Revision E