The x48 connector is described as being in the RH rear door sill. We had a similar problem on a 300E and the problem was some where under the carpet (I saw the damage but don't remember except it was on the floor - could have been under a seat. The connector you are looking for x48f is grouped with x48d and x48e. The other connectors x48a,b,c are identified as antitheft harness, described as base of right hand door pillar. Unfortunately there are no pictures for that connector.
Bosch Master, ASE Master, L1
33 years MB technician