Out of the blue, my wife's ML320 won't start. It cranks strong but won't fire up.

After searching the forum for similar problems, looks like fuel pump relay is logical place to start. Ordered one from my favorite supplier here in Virginia. She had to order it from California though....

My question is she said it looks like a relay that serves a lot of functions besides the fuel pump. I checked on the web and the description from a supplier below is what I found:

"Parking light : Horn : Fuel Pump : Blinker : Starter Motor : Circulating Pump : Foglight : Rear Defroster "



Looks like a multipurpose relay alright. But can the fuel pump function in this multipurpose relay go bad alone without the rest going bad as well?

Or am I replacing the wrong part?

Also, if it's not the relay's fault, where should I look next, and next after that?


Pls. help!!!



thanks!!