fuel pump relay on a 1989 300se

[mountainman]

My 300se broke down the other day, to be told by thee AA that it was possibly the fuel pump relay as there was no power going to the fuel pump. The only trouble is that the AA guy didn't know where it was and the mercedes main dealer mechanic told me the relay is by the battery but doesn't appear to be there either. Could somebody please help me and if possible where i can get the part without going to the stealership. Once i find where the relay is can they be repaired?.
Look forward to your help
Mountain Man.

 

[Shude]

I'm calling this engine section material, moving!

 

[mountainman]

thanks for the help shude.

 

[guydewdney]

on the firewall - pn 003 545 24 05 - it shows on my epc as on the left, but thats lhd - so it might be on the right..

 

[pentoman]

There should be a black box, about the size of a cigarette packet, 'on' the firewall.. roughly where the bonnet hinges attach to the car. You might have to move a flappy plastic cover to get to it.

I'm only speaking for a 190E, but a 300 shouldn't be too different. The box may have 'kickdown' written on it, and pulls out by hand.

I resoldered the dried joints in mine over 2 years ago, no problems since! Before that, the fuel pump was not running. Common problem with the four cylinders... not sure about your six?


Russ

 

[mountainman]

thanks for replying guys, i will check again in the morning but all the places where it is supposed to be there isn't anything. i looked under a friends mercedes 300e and found his straight away but under the bonnet did not resemble mine at all. without my merc i cant wear my crown and my friends dont wave anymore.

 

[guydewdney]

does your chassis number begin 126.024?

A 300e is a different beastie...

the epc does state 'up to end of 89 - on the 90 version i dont know

definately a big fag packet sized thing, big chuinky round pins (by the look of it) on the firewall - with a couple or 7 other relays next to it - all mounted on a bracket.

 

[pentoman]

Whoops.. misread it - yours is a 300SE and I thought it was a 300E.

Hmm... not sure what things are like on that then!

good luck

Russ

 

[mountainman]

thanks for the help guys, i have finally found the relay where the main dealers told me it definitely wasn't. For other s class owners it is situated in front of the fuse box by the brake servo . I put a wire across the terminals and the pump worked so i know the relay needs changing. The relay from the main dealers is £76 plus vat, but i have found a mechanic who only deals with mercs and has loads of spares who will sell me one for £45 inc. For a relay i still find this is really expensive but my car will be mobile and i can look stone-faced again when people see me in it.

 

[mountainman]

one more thing, can relays be recontioned or repaired?

 

[Will]

The fuel pump relay doesn't just contain one, simple relay!

From memory, it has a number of other components, which are responsible/linked the kickdown (on automatic models), the cold start system and a rev limiter.

I think £76 + VAT new is a fair price, but I think the reason they aren't cheap s/h is because they are a common item to fail!

Common fault on older MBs - I had to replace one on my old 190E 2.3-16v. It was situated between the battery and the firewall, just behind a plastic panel.

HTH,

Cheers,

Will

 

[pentoman]

one more thing, can relays be recontioned or repaired?

Yes. I did mine a couple of years ago when it eventually failed completely, and have had no problem since.

Open it up (should just pull apart) and look for any broken/weak solders. Mine were where the relay(s) attach to the circuit. The relays are the big ugly copper things!

I just resoldered and all was well. Do a good job while you're there so you can put it out of your mind and know it won't cause problems again.

Russ