Fuel Pump Relay/Socket burnt! WTF
Thread Starter
Junior Member
Joined: May 2011
Posts: 38
Likes: 2
From: Bay Area, CA
2003 E55 AMG
Fuel Pump Relay/Socket burnt! WTF
I recently had my fuel tank and fuel pump assembly replaced under warranty. The SA said they also replaced my fuel pump relay and fuse which were burned out. A week later the fuel pump relay burned out again. I checked out the fuel pump/sender unit and it is a new unit, the connections were all fine. How could a brand new fuel pump assembly burn out the relay within a week? What are some other causes that can the relay to burn out?? Checked the battery voltage just in case and it was good as well. Any suggestions??
MBWorld Fanatic!
Joined: Jan 2016
Posts: 2,749
Likes: 881
From: In the Shadow of the Tetons
2013 ML350 Bluetec
Crappy relay sockets are a well-known problem with these cars. Do a search and find how to replace the socket. Problem solved.
A loose socket will not make great contact with the relay tabs. Poor contacts mean resistance means heat means melted plastic.
A loose socket will not make great contact with the relay tabs. Poor contacts mean resistance means heat means melted plastic.
Thread Starter
Junior Member
Joined: May 2011
Posts: 38
Likes: 2
From: Bay Area, CA
2003 E55 AMG
Thanks for the reply I will look into getting a replacement socket. I am thinking that if I replace the socket with the oem socket it will burn out again. I did notice that bbirdwell did an upgrade to the stock socket but I'm not that handy especially when it comes to electrical ...anyone else replace the burnt stock fuel pump relay socket? If so did you replace it with the oem version or use an upgraded one like bbirdwell? Once again thanks for all your assistance . Any help is greatly greatly appreciated !!
MBWorld Fanatic!
Joined: Jan 2016
Posts: 2,749
Likes: 881
From: In the Shadow of the Tetons
2013 ML350 Bluetec
I've had good luck using dielectric grease, liberally applied to the socket, to help with heat dissipation. If I do run into the fuel pump relay socket problem, I'd be inclined to just get a new OEM socket and pile the grease into it before plugging in a new relay.
Member
Joined: Mar 2017
Posts: 157
Likes: 27
From: Arizona
2004 E55
I replaced my fuel pump relay and socket withe the higher capacity one in Barry's thread. I wasn't that difficult to do if you know how to crimp and solder. Just do them one wire at a time before you remove it from the old socket. Once I had the trunk liner out it took me about 20 mins to do. I highly recommend you do this or have someone that knows how to solder do it.
