As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 6339 - IAD-EWR - DURING TAXI, AIRCRAFT RETURNED TO GATE DUE TO LEFT BETA WARNING LIGHT WOULD NO ILLUMINATE. MAINTENANCE INSPECTED AND REMOVED AND REPLACED BETA PRESSURE SWITCH, OPS CHECK OK. AIRCRAFT WAS RELEASED AND APPROVED FOR RETURN TO SERVICE. (M)