What was found
FOUND TRIM MASTER SWITCH PREVIOUSLY REPAIRED WITH GLUE. REPLACED SWITCH, NEW SWITCH FELL APART AT FWD SEAM AT FIRST OPS CHECK. SECOND NEW SWITCH DID THE SAME. BACK PART OF SWITCH FELL INTO CENTER CONSOLE, SHORTED OUT ON A/F STRUCTURE AND COULD NOT BE RETRIEVED TO SELECT TRIM OFF. POOR DESIGN OF SWITCH ASSEMBLY AND POOR CONSTRUCTION OF SWITCH. REPLACED SWITCH WITH ONE OF HIGHER QUALITY AND MADE BY A DIFFERENT MANUFACTURER. FAA FORM 337 AND FIELD APPROVAL GRANTED FOR CHANGE.