2014 GMC TERRAIN Structurebody Problems

All wheel light say it’s disabled

THE POWERED LIFT GATE RAISED ALL THE WAY UP (AS REQUESTED), THEN DROPPED UNEXPECTEDLY ON MY WIFE'S BACK AND HEAD THEN RAISED AGAIN THEN DROPPED AND LATCHED. THE POWERED LIFT GATE REPEATS THIS UPON EVERY REQUEST TO OPEN AND WILL NOT REMAIN OPEN, MAKING THE REAR CARGO AREA BASICALLY USELESS. THE LIFT GATE IS VERY HEAVY AND COULD POSSIBLY INJURE SOMEONE WHEN DROPPING DOWN UNEXPECTEDLY. THE VEHICLE WAS PARKED IN OUR GARAGE UPON THE FIRST TIME AND THE VEHICLE HAS BEEN PARKED EACH TIME THE LIFT GATE WAS REQUESTED TO OPEN.

PURCHASED A 2014 GMC TERRAIN CERTIFIED FROM A DEALER AND IT HAD VISIBLE RUST ON DRIVERS SIDE REAR PASSENGER DOOR HEM. IT WAS TAKEN TO ABRA AUTO BODY SHOP AND WORKED ON 3 TIMES WITH THE RUST COMING RIGHT BACK THROUGH ONLY AFTER 7 DAYS. IT WAS SEAMED AND SEALED FOR A FINAL TIME AND THE AUTO BODY SHOP EVEN ADMITTED IT WILL NOT STOP THE RUST AND RECOMMENDS A NEW DOOR SHELL. HOW CAN A CAR ONLY 2 YRS 10 MONTHS OLD HAVE THIS BAD OF RUST? OTHER 3 DOORS HAVE VERY LIGHT SPOTS AND FRONT END FENDER PANELS AS WELL. HUSBAND ALSO PURCHASED A 2013 TERRAIN AND IT HAS SAME ISSUES.