300e fuel pump relay - PeachParts Mercedes-Benz Forum

Sylvester · #1 09-09-2007, 12:12 AM

hi.. do anyone know how to check a fuel pump relay to see if its bad or not thanks for the help.

brewtoo · #2 09-09-2007, 08:30 AM

What year is your car? The early cars have a separate relay. The later cars have it built into the Klima relay.

Sylvester · #3 09-09-2007, 09:07 AM

hi.. my car is a 1986 mercedes 300e

brewtoo · #4 09-09-2007, 10:22 AM

OK, I don't remember which pins to jump, but if you do a search you will find it mentioned a number of times.

BTW, what are your symptoms?

ashkiiyazhi · #5 09-09-2007, 04:46 PM

look under diy links - fuel systems - gasoline engines . . . .

I was recommended the 30 and 87 pins and to use pliers to remove jumper when done because it gets really, REALLY, RREEAALLLYY HOTTT.

emphasis on last part because I ignored the "warning"

saumil · #6 09-09-2007, 10:30 PM

Use a thick cable to jumper, thicker the cable, less the resistance and less hot it will get. Thickness close to the relay's pin (12 gauge perhaps).

865sp300e · #7 09-10-2007, 10:27 AM

Quote:

Originally Posted by brewtoo

What year is your car? The early cars have a separate relay. The later cars have it built into the Klima relay.

The 1986 300E has a separate fuel pump relay located next to the klima relay. If you jumper the pins identified previously you will hear the fuel pump run. Its an easy and quick test. A search in this forum will give you everything you need to know and more.