Tailgate woes on S211 Wagon

[idlerider]

The tailgate on my E350 has started not to latch nor lift/lower the load cover correctly. The 'lower' button on the base of the tailgate is inoperative until the car has been driven some distance - even with the battery on overnight charge. When lifting the tailgate with the remote control, the door sometimes emits three 'beeps' as it lifts. When lowering, it will latch about one time in ten and only if pressure is applied to both sides of the door for the last 20-30 cms. Can anyone with experience of this fault suggest a cure?

 

[idlerider]

UPDATE: problem solved! - it was the lock all along. It seems they're a known problem with W/S211s - one guy on the internet (US) said he bought his w211 new in 2005 and so far has had the lock replaced six times - the first one, under warranty! I replaced the lock and all the issues disappeared.
Here's a word of warning, though: if you have an S211 with the 7-seat option, it will have an interior tailgate handle – the locks are different! As well as the usual red cable for the exterior handle, they have an additional yellow cable for the interior handle - and they're not interchangeable.
Hope this helps someone.