ok here's my collection, the key is to understand how the relays have to be wired and how you splice into the harness (it's just one wire that drives the pump):
(this was the approach i took)
Simpler method than mercedesshop procedure
They are all hard to digest and you have to map out all the different pieces of information.
I would get the remote unit working before installing and make sure it supplies the +12v and ground as required before hooking anything up. I used a lantern battery for this purpose. Then I would get it working locking and unlocking the car and last I would hook up any light flashing / beep convenience features(don't have those links cuz i didn't do em).