Mercedes-Benz Forum banner

Why can't I buy a fuel pump relay?!

2.9K views 19 replies 7 participants last post by  288369  
btw, the mercedes EPC is free for 1 year subscription at http://epc.startekinfo.com for US models and non-commercial usage. its a Java app thats launched from their website. registering requires a credit card (god knows why) and although it says it takes american express, it will error, unless you use a visa/mastercard. :dunno:

if you put your VIN into the EPC application, it goes directly to your model car, it has the datacard for it and everything.

this is the same EPC that dealers' parts counters use, but without pricing or direct ordering ability. you can, however, build shopping lists and such.
 
Rick

What steps have been taken that assure you your the fuel pump relay is bad?
very good point. *I* would use a digital multimeter to test that the signal to the coil is coming on when you expect it, and that there is power at the relay input, and that the relay switch closes when it should. the relay has a fuse on it. I would also test that power is getting to the fuel pumps (unplug the pumps, and check for volts across the connector to said pumps).

assuming its like my Volvos, the fuel pumps only come on for about 1-2 seconds when you turn on the key (to prime the pressure), then switch off until the motor is turned over. when the motor stops turning over, the pumps stop again a second later.