When I had the heated seats on my 08 C14, I always had a hard time getting the rear tang on the back seat to engage the mechanism that the tang fastens into. Do not know if that made much sense or not. Anyway, I found the rear tang was a tad too short so I unscrewed it, put a couple of small washers on the part that screws into the seat thus making the tang go down further and this eliminated all my problems with the difficulty of securing the back seat. I think it made the tang a quarter inch longer.