Can anyone recommend someone that will rebuild a fuel pump relay? I now have a couple of bad ones and it does not seem like rocket science to fix them. Might be a decent side business for one of you electronic techs out there.

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'76 240D-Sold
'78 240D-Sold
'85 300 SD, 165K-Sold
'88 300 TE, 165K-Sold
'64 Porsche 356C Cabriolet- under restoration
'86 560SL 124K Miles-Sold
'94 320E Wagon, 74K Miles-128K Miles JUNKED
'06 E350 Wagon, 84K Miles
07 SL550, 14K Miles

The problem is that cost on a new one is cheap and the cost of a tow truck is expensive if your $100 dollar, low margin part fails.
See? It really makes no sense to rebuild a part that costs less than $100. I am talking about dealer Net. Not retail.

BTW, I have about 50 of them in a box.

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Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS

I have a 93 190E 2.6. When do I need to change this?

Ron,
I have an '85 500SEC. I have repaired my FPR. It took all of 15 minutes.
What you probably have is a bad ground/support.
Look on the backside of the larger of the two solenoids, at the bottom(pin end) of the circuit board.
The main bracket for the coil of copper wire is also the electrical ground, for the fuel pump relay.
I found mine to be cracked and corroded. Dissimilar metal.
I took a small stiff bristle brush; a little flux and my $15 soldering iron, and re-soldered the joint.
It hasn't missed a beat since(6mos).
I did buy a second FPR, prior to fixing the original. I found it to have the same problem. I carry it in the boot, just in case.
As a side note, the smaller of the two solenoids is the over-rev cut-out, I believe.
Good luck, John F.

Soldering will temporarily fix the problem but could cause future intermittant problems, later. Just replace it with a new one. My relay on 300E went out and I had to get towed to the mechanic. The relay on mine broke just when I was ready to drive to Las Vegas.

Send it to me, I will take care of it.

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I got too many cars!! Insurance eats me alive. Dave

78 Corvette Stingray - 3k
82 242 Turbo Volvo - Manual - 270k
86 300e 5 speed manual - 210k
87 420sel - 240k
89 560sl - 78k
91 420sel - 205k
91 560sel - 85k
94 GMC Suburban - 90k
97 Harley Davidson Heritage Softail - 25k
00 GMC Silverado 1 ton 30k

Many thanks folks, I did a magnified inspection of the board in bright light and found two suspect contacts. A careful resolder and the unit works fine.
The logic of replacing a suspect unit completely instead of fixing it is certainly valid, but there is surely something to be said for fixing the original and keeping it in the car to use as a spare when/if you again get a relay failure. It will save the $100 tow.
I'd love to know if you can safely swap these relays between cars. The one from the 190 will start the 300 and vice versa, but I wouldn't actually want to drive a car with a swapped part as perhaps it could damage a system. Any knowledge out there?

__________________
'76 240D-Sold
'78 240D-Sold
'85 300 SD, 165K-Sold
'88 300 TE, 165K-Sold
'64 Porsche 356C Cabriolet- under restoration
'86 560SL 124K Miles-Sold
'94 320E Wagon, 74K Miles-128K Miles JUNKED
'06 E350 Wagon, 84K Miles
07 SL550, 14K Miles

Also, keep a small piece of insulated wire in your trunk (14AWG or so) with the ends bared. In a pinch, insert this to short terminals 7 and 8 on the relay holder with the relay removed (works on my 1990 560SEL) to get the fuel pump running - gets you home - but remember to pull the wire as the pump will continue to run when the ignition is shut off.

You lose the rev limiter this way, so be careful.

Good suggestion! You can also pull the cover off the relay and put jumper clip leads on 15 and 87 and then reinsert the relay. Then join the two leads and the pump should start. This does exactly the same thing that jumping 7 to 8 does, but it is perhaps a bit easier to do.

__________________
'76 240D-Sold
'78 240D-Sold
'85 300 SD, 165K-Sold
'88 300 TE, 165K-Sold
'64 Porsche 356C Cabriolet- under restoration
'86 560SL 124K Miles-Sold
'94 320E Wagon, 74K Miles-128K Miles JUNKED
'06 E350 Wagon, 84K Miles
07 SL550, 14K Miles