Relay assignment of fuse and relay box in trunk - GF54.15-P-1257-04SX

MODEL 221.0 /1, 216.3 up to Model Year 8 

Fig 1: Rear SAM Control Unit With Fuse And Relay Module - Model 221.0 /1, 216.3 Up To Model Year 8

Courtesy of MERCEDES-BENZ USA

Relay Identification	Designation
M	Terminal 15 relay (N10/2kM)
N	Terminal 15R relay (N10/2kN)
O	Power outlet relay (N10/2kO)
P	Heated rear window relay (N10/2kP)
Q	Charge air cooler circulation pump relay (N10/2kQ)
R	Cigar lighter relay (N10/2kR)
S	Fuel pump relay (N10/2kS)