Ignitor comes to mind. Open PF
capacitor would be the other thing. Unless the HV pulse is there to
strike the lamp, the logic will notice that an arc was not produced in a given time and it will
throw an error. Since the lamp is know good, the other four suspects are wiring/fuses,
Ballast,
Capacitor, and the ignitor. (My recall is this is a magnetic
ballast.) If it was the cap, you would probably hear the zap of the ignitor trying to
strike. Since all you hear is the click of a
relay, then I question the ignitor. Can't rule out wiring as it is a moving light and thus a lot of flexing goes on.
The
ballast could be ruled in or out if I had the wiring diagram handy which I don't. If it is a stand-alone ignitor then the
ballast is probably ok. If it is an ignitor that uses a
ballast winding to kick the HV, then the
ballast can't be ruled out.
Again, all based on it being a magnetic. Electronic ballasts would be a different story as those pretty much do everything on board. The PDF I just looked at says Electronic, however I am not sure this applies to all units.