2001 s430. When closing the driver door the assist tries to close the door but just hisses?? The shop saidthatthe door latch assembly needs to be replaced which runs around $800 bucks ouch!!! Any thoughts? How easy is it to get at and replace/repair this part?[:@]

 

Diagnosis sounds correct.
Not sure if the unit can be fixed DIY however may be as simple as the vac/pressure connection not fully home. I'd go for this later possibility and have a look.
Tedious trying to get to anything in the door/B pillar but basically straightforward. Lots of hidden fixings which are easily damaged unless you are very careful or use the correct wedge tools.
Never actually worked on a door assist version. Is the "pull close" mechanism in the latch or the "goal post"/Hasp?
Stuart.

 

It's in the latch itself. Thank you for your response.