What was found
APU DETECTOR INOPERATIVE LIGHT, ALONG WITH OVERHEAT/DETECTOR MASTER CAUTION LIGHT FLASHES CONTINUOUSLY AFTER REACHING TOP OF CLIMB. ACFT GROUNDED. DVI ON C403 C/B, NO DEFECTS NOTED. DUE TO C/B FOUND OUT. R & R M279 ENGINE/APU OVERHEAT DETECTION MODULE REF AMM 26-10-01. GVI APU FIRE DETECTOR LOOP, FOUND WIRE W7538-6001R-18 AT UPPER DETECTOR LOOSE ENOUGH THAT WIRE LUG CAN SLIDE ON DETECTOR STUD, CONNECTOR SECURED REF WDM 26-11-31. ENGINE AND APU FIRE TEST NORMAL.