1989 W124 300E fuel pump relay location
 

Can anyone tell me where I can find the fuel pump relay? I've looked all around under the hood and under the back seat. Any suggestions?

Thanks,
Razor

There is a plastic panel behind the battery that when removed exposes the fuel pump relay, klima relay, overvoltage protection relay, ABS controller and engine controller.

can be a pia to pull...but i do it without removing the batter... my black panel just sort of sits in there...

It's the one in the area already described which has an RPM listed on the top, it also has the number of cylinders, "cyl" abbreviated the German "zyl", 6 zyl for example. The Klima is the climate control (a/c clutch) relay. The OVP looks nothing like these 2 relays.

I pulled the relay out without too much difficulty. I then gave it the Fonzy tap and reinstalled it. As soon as I turn the ignition switch I could hear the electric fuel pump running to charge the system. The car started without a problem. I tried starting it several times without a problem. Do you know if there is a bench test that can be done to check out the relay?
I will be ordering a spare relay to keep in the glove box.
Thanks for all the help.
Razor

Those relay modules are notorious for bad solder connections.

If you have any soldering skills you should be able to fix it yourself. You need to remove the silicone sealer that they use to weatherproof the module and then you can pry it apart.
Resolder all of the connections of the relays that you will find inside where they mount on the printed circuit board. You will likely be able to see cracks around the terminals.

If you aren't confident with soldering, any TV and radio repair shop will resolder it for you for a reasonable price (should only take a few minutes).

Those circuit boards are wave soldered initially and the process does not put enough solder on larger items such as relays. Thermal cycling and other stresses eventually cause the solder to crack giving intermittent conditions.

This relay tends to get damaged at the solder points on the circuit board. When I opened my old one, a copper film running from a coil actually burned up. Jumped/soldered the film with a regular telephone wire and now it's working. I keep it as a spare.

Thanks for the info. I will purchase a new one and open the old one and resolder the connections.
Thanks again.
Razor

Well.. if what i've been told about the relay is correct, 87 and 30 are the relayed points.. i've proven this when i take it apart. I can test continuity between 30 and 87 and get none. Manually push the relay together and they get continuity. so, that would give you a bench test to see if your circuit was connecting? at least.. in that particular place.

Why would you expect to get continuity between 30 and 87 if the relay is out of the car?
Gilly