Turned out that the Smoke detector in the baggage hatch had a wire broken free, touching the plug shell.
Disconnecting either pilot or copilot ANN COUPLER on the zero door will clear the fault. No FD annunciators test in any condition.
R and R 1 pc card in the copilot ann box, now Pilot fms ann test good, copilot dark. Now AUX bus must be on to get it to pop. Pilot side still ANN good.
Harness labels:
NTE5256A zener in the ann couplers