What was found
WHILE PERFORMING TASK 78-31-00-710 THE MASTER WARNING LIGHTS DID NOT ILLUMINATE; STEP C., (4), (B). ON JACKS IN AIR MODE, HYD PRESSURE AVAILABLE, ATTEMPT TO DEPLOY THRUST REVERSERS; THURST REVERSERS SHOULD NOT DEPLOY, ARM LIGHTS SHOULD ILLUMINATE AND MASTER WARNING SHOULD ILLUMINATE. TESTED OTHER SYS THAT WOULD ILLUMINATE MASTER WARNING; MASTER WARNING WOULD NOT ILLUMINATE. OHMED OUT MASTER WARNING CIRCUIT WIRING AND FOUND BROKEN GROUND WIRE SOLDER CONNECTION ON BACK OF PILOTS MASTER WARNING SWITCH LIGHT. RESOLDERED WIRE TO SWITCH LIGHT.