What was found
PRIMARY STAB TRIM FAILED CLIMBING THROUGH FL280, NO CAS MESSAGE PRESENT. (10-29-07) R & R HORIZ STAB ECM IAW MM 27-40-00. CHECK OK. PERFORMED VOLTAGE CHECKS ON ECM CONNECTORS PV003 & PV004, VOLTAGES & GROUNDS OK. RECEIVED POWER TO BOTH SEC. & PRIM. ACTUATORS. PERFORMED RESISTANCE CHECKS TO BOTH SEC. & PRIM. CLUTCH & BRAKE ASSY, CHECKS OK. TROUBLESHOOTING FOUND CONNECTORS PV003 & PV004 SWAPPED. CONNECTORS CORRECTED & PROBLEMS MOVED TO SECONDARY STAB & MOVING INTERMITTENTLY. CLEANED & TIGHTENED CONNECTORS, NO HELP. ECM BAD. TROUBLESHOT IAW MM 27-40-00 & CESSNA 750 EXPERT SYS. REMOVED ECM & INSTALLED MODIFIED ECM. PERFORMED PRIMARY CHANNEL A/B TRAVEL CHECKS PER MM TASK 27-40-00-721, NO FAULTS NOTED.