Read the pcmaher link to understand the operation, but I think
you have a fuse problem (or 2, since both of them
are out of order). Look in the fusebox in the
trunk. Are any fuse blown there? The number 3 fuse lists as both
central locking and closing assist in a diagram I got. Number 9 is
the closing assist pump alone.

I do not know for sure, but I think both pumps are connected
to a convenience control module, on the same side of luggage as
the fuses, under the lining, that may have failed.

br,
syljua
1998 W140 S320