Thank you Mick J
For the complete explanation for those conections.
Yesterday I had the opportunity to speak with an MB technician. I told me about an more hole situated between 30 (D) and 87 (I) preventing the mismounting of the relay.
And he also told me to jump the contact of each side of this hole (30 & 87) to have the pump functionning all the time.
And I totaly agree with you concerning the pins to use.
I just want to make this brigde to ensure that is (or is not) this relay the cause of my problem.