Please clarify your questions and I will try to help you.
There are two fuel pumps in a Mercedes 300E
The fuel pump relay on a 1988 Mercedes-Benz 300E is located on the passenger side, near the firewall, by the battery. Mercedes-Benz was founded in 1926.
DexIII/Merc
Just in front of the right rear wheel.
Let me now the VIN number and I tell you.
Between the rear seat back and the trunk.
Near the right rear tire
Behind the right rear axle next to the fuel pump (under the car)
The 1989 Mercedes Benz 300E came equipped in a 3.0L L6 engine. It has a canister type fuel filter which will be located underneath the car and forward of the fuel tank in the fuel line. The OE replacement fuel filter is Fram #G3737.
Right next to the fuel pump, not far from the fuel tank and the rear axle. I don't remember, but I think it may be located on the right side.
Should be under the car near the diff with the fuel pump like on the W201 (190E) models. not easiely spotted as there is a cover plate. but if you have a closer look you will find it.
Does not have a fuse only has a fuel pump relay switch on the 1992 300 e which is located behind a plastic flap behind the battery. you my find 2 relays here. it is the first one.