It's near the right rear tire.
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.
There are two fuel pumps in a Mercedes 300E
one fuel pump. Why are there so many unanswered questions?
Just in front of the right rear wheel.
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.
Near the right rear tire
Between the rear seat back and the trunk.
Behind the right rear axle next to the fuel pump (under the car)
The fuel pump on a 1986 Mercedes-Benz 300E is located in the fuel tank. It is usually accessed by removing the rear seat and the access panel in the trunk area. Once the panel is removed, you can reach the fuel pump assembly for inspection or replacement. Be sure to disconnect the battery and take safety precautions when working with fuel systems.
The relay is a black retangular box located between the battery and the firewall.
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.
Attached to the fuel lines that come off the fuel distributor. Follow the lines towards the head. Hope this helps.