Safety problem with the power liftgate on 2008 buick enclave. when closing, it does not reverse at my shoulder height. a few days ago, it pushed me down to about to halfway point before it stopped (ouch!!!) later tried this a few times... in the first 6-12" of closing, the gate does not reverse, even with very firm hand pressure. further tests showed that it fails to reverse at even more that the 12" mark (i didn't measure). at about midway to closed, it reverses with just a light touch. according to owners manual: * "if the liftgate encounters an obstacle during a power open or close cycle, a warning chime will sound and the liftgate will automatically reverse direction to the full closed or open position." *tr