Style_Front

So the other day at a stop light my car died in the middle of traffic.

damn it.

Thought it was the fuel pump. I had it towed and when I got off the tow truck I accidentally turned the key and it started right up. WTF?

The following day I come out and try to start it. No luck. I was working the diagnosis and after a few attempts to start it started right up about the 5th time. I was just turning the motor to try and listen for the pump or any other unusual sounds. I let it run for about a minute and walked in to grab a drink. By the time I got back it died and wouldn't start again. So time to start trouble shooting.

Checked the fuse. It was the wrong fuse in position 4. 7.5 amp instead of 20 amp. However it was not blown. I put the 30 amp fuse from my power seat and tried to start the car. No luck. Next I pull the fuel relay in position A and swapped it with a matching unit from under the hood, I believe it was the fan relay in position O. Tried to start it. No luck.

So I pull the pump out, hook the positive and negative inputs from the pump directly to the car battery and the first pump throttles up first time with no issue at all. Repeat the same test for the second pump with same results.

Pumps work when powered directly to 12 volt battery. I check the harness that plugs into the top of thepump and turn the car on, no observable voltage or power registered on my volt meter from any of the pins. I go the next step down the line to my fuse box and see if theres any voltage registering from the fuse position 4 with key in second position. Zero voltage.

This is where im at. If any one has any idea why power would not be passing through fuse 4 let me know. Power was passing through fuse position 5 and up. No voltage could be measured through fuse position 4 and below.

Thanks for any help.

bbirdwell

If you have an AMG you need to read more in this sub-forum. AMG fuel pump relay is on the passenger side of the trunk behind the panel; no access except to pull the panel. The fuse in position 4 is for the heat exchanger coolant pump. If a 2003 or 2004, you'll find the air pump relay over the auxiliary battery. The relay in the front SAM that, in the non-AMG, is for the air pump relay is wired for the AMG oil cooler fan on all models E55. So, 2003 and 2004 have one relay on the passenger side of the trunk and it is for the fuel pump. 2005 has two relays on the passenger side; one fuel pump and one air pump. 2006 has three relays on the passenger side of the trunk; two(!) for fuel pumps and one for air pump.

Start here and read all the way through.
https://mbworld.org/forums/w211-amg/...intenance.html

Style_Front

I have a 2005 E55 AMG, heres the vin break down. I have tried looking for relay and fuse schematics specific to my car cause Mercedes thought I would never need that info on the inside of my fuse lids (arseholes!)

Model E 55 AMG, Type Code 211, Sub Model 076, Engine 113990 60 037571, Transmission 722643 05 802310, Order Number 0570677880, Production Number 8620538, Delivery Date Nov 22, 2004

Style_Front

This is the information I've been operating on.

http://www.mercedesmedic.com/fuses-w...-2008-e-class/

bbirdwell

The E55 AMG has four different wiring harnesses depending upon date of manufacture and none of them match the non-AMG vehicles which is the fuse information shown in the link.
Harness #1 used up to build date of 20 March 2003.
Harness #2 used from 21 March 2003 to 31 August 2003.
Harness #3 used from 1 September 2003 to 31 May 2005.
Harness #4 used as of 1 June 2005 until the E55 was replaced by the E63.

Key points:
-Non-AMG fuel pump fuse and relay in rear SAM = AMG heat exchanger coolant pump fuse and relay
-Non-AMG air pump fuse and relay in front SAM = AMG oil cooler fan (located under passenger side front fender liner)
-AMG fuel pump fuse and relay located on side on trunk next to airmatic pressure tank
-AMG air pump relay located over auxiliary battery (2003 and 2004 models)
-AMG air pump fuse and relay located next to fuel pump fuse and relay in trunk (2005 and 2006 models)

Check PM.

Style_Front

Yup, I'm harness 3

08E63AMGboy

Is this the same for e63 ? Or is our fuel pump relay on the left side in trunk??

bbirdwell

The E63 does not use relays. The E63 has two each Pulse Width Modulated (PWM) fuel pump controllers located on the passenger side of the trunk in the left hand drive car. You will also find a fuse for the PWM modules and a fuse for the secondary ear injection pump on that same side.

08E63AMGboy

So same for a right hand drive car ? Happen to have a pic or diagram of these PWM'S in question. Never seen 1 b4.