The neon light should be on whenever the system's blower fan is on. When the system fan shuts off, the neon light should also shut off. If this is not happening, please follow these troubleshooting steps: Make sure the electronic cells are clean, dry and properly installed. Make sure that the pre-filter is in the cabinet slot farthest from the furnace. With the access door closed, turn on the Electronic Air Cleaner and the system blower fan. If neon light is on, the Electronic Air Cleaner is working. If the neon light is off, turn the Electronic Air Cleaner off and remove cells only (not the pre-filter), then close the access door and turn on the Electronic Air Cleaner (fan should still be on). If the neon light does not come on, contact your contractor for repair. If the neon light comes on, inspect the cells for bent collector plates, broken ionizer wires, dirt on insulators, and damaged ionizer or collector contact tabs. Bent collector plates can be carefully straightened and broken ionizer wires should be replaced. All other repairs should be undertaken by your local heating and cooling contractor.