As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AT THE START OF ENGINE NUMBER 1 RED FIRE WARN LIGHT CAME ON WITH NO FIRE BELL AND NO FIRE INDUCTION ON FIRE HANDLES. WHEN FIRE WARN BUTTON WAS PUSHED THE LIGHT WOULD NOT EXTINGUISH. RED FIRE WARN LIGHT WOULD ONLY EXTINGUISH WHEN APU BLEED SWITCH WAS SWITCHED OFF AND LEFT PACK WAS TURNED ON. REMOVED AND REPLACED ENGINE AND APU FIRE DETECTION MODULE. PER AMM 26-10-01.