After a two week hibernation the 300SE refused to start . Ignition on the fuel pump buzz was missing . I cleaned the Fuel relay pins and the car started fine but soon the intermittent engine cut-outs came back.

Much Earlier on i had re- soldered the fuel pump Relay joints so i decided to replace the unit .The replacement !0 pin relay replaced the 9 pin unit perfectly . A very responsive and reliably running engine now.
The 4 & 6 cyl relays are interchangeable, only that the rev limiter cuts in earlierwhen installed on a 6 cylinder model.

mak
300se 89
euro