What was found
APU SHUTSDOWN. NO FAULT LIGHT. NO ABNORMAL INDICATIONS. IAW T-S REPLACED APU FLOW SENSITIVE MODULE, NO HELP. REPLACED GCU IAW AMM, NO HELP. REPLACED BPCU IAW AMM, NO HELP. RESTORED ORIGINAL UNIT. CKD GEN FEEDERS AND LUGS. ALL OK. RUN APU WITH 70 PERCENT OF LOAD FOR 30 MINUTES THEN DROP OFF LINE TRIED TO RECONNECT SHOW APU FIELD OPEN MOMENTARY WHILE TRIED TO RECONNECT APU GEN. R & R APU GENERATOR IAW MM. OPS CHECKS NORMAL. RESET SYS CRANK APU WITH NO FAULTS. REPLACED LOW OIL TEMP SWITCH AND STARTED SEVERAL TIMES, OPS CKS NORMAL.