UNIT TURNED OFF ON ARRIVAL. NO COOLING CALL. PREVIOUS TECH WAS OUT DAY BEFORE TO TROUBLESHOOT. TRANSFORMER KEPT BLOWING LOW VOLTAGE FUSE. TECH SUPPORT HAD THEM GO THROUGH SEQUENCE OF TEST WITH NO SUCCES. COMPRESSOR WOULD COME ON BUT NOT CONDENSER FAN. NOTICED ARC MARKS ON BOTTOM OF CONDENSER CONTACTOR. OHMED OUT CONTACTOR AND EVERYTHING TESTED FINE. TO CONFIRM I HOOKED MY CONDENSER FAN WIRES TO THE IND. MOTOR CONTACTOR. AND GOT SAME RESULTS. STARTED TRACING WIRES AND FOUND FACTORY SPADE CONNECTION NOT MAKING FULL CONTACT. MADE CONNECTION AND WIRED EVERYTHING BACK UP AS IT SHOULD. CALLED FOR COOLING FROM THERMOSTAT AND UNIT WOULD NOT FIRE UP, HOWEVER IF I USED JUMPERS AT THE UNIT EVERYTHING WORKED FINE. OHMED OUT STAT WIRES AND WAS GETTING RESISTANCE WHERE THERE SHOULDNT BE ANY. REMOVED STAT FROM WALL AND WIRED DIRECTLY TO UNIT UP ON THE ROOF. EVERYTHING WORKED AS IT SHOULD. TRIMMED WIRES BACK WHERE STAT WAS INSTALLED AND REWIRED STAT. CYCLED POWER ON UNIT, AND THEN GAVE A CALL FOR COOL