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.
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 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.
DexIII/Merc