Mercedes 230 E ( W123 ) fuel pump relay - Mr Fox
Hi Everyone,

I have had a problem with my Mercedes today, the first ever, where it would not start, the fuel pump ( electric ) was not running, so I took a live feed from the battery to the pump, and it started without a problem, and continued to run fine and restarted, even after I removed the improvised feed.

I suspect the Fuel pump relay to be at fault, however I could not locate it anywhere, despite reference being made to it in the Workshop manual, as being on the LH Front inner wing.

Does anyone know where this component can be found, what is likely to have caused this malfunction, and anything else I should be looking for ?

Many thanks, and Happy new year to all backroomers

Mercedes 230 E ( W123 ) fuel pump relay - Aprilia
Right at back (on the firewall) on the nearside?

Might also be inside the car (in gearlever console surround?).
Mercedes 230 E ( W123 ) fuel pump relay - elekie&a/c doctor
sounds very likely to be fuel pump relay.Located inside car either drivers side dash panel above kickwell plastic panel or passenger side above kickwell panel to left of glovebox.
Mercedes 230 E ( W123 ) fuel pump relay - Aprilia
Location does depend on the year of the car (which you don't give).
On earlier W123's it is located just under the dash, above the bonnet release lever in the passenger footwell. In the last 2 years of production they reloacted them to in front of the fuse box, and I once replaced one on an estate where it was inside the gearlever console trim! (as mentioned in earlier post).

The part number is 001 545 07 05. They are expensive from the dealer (about £70+VAT IIRC) but you can pop the cover off and reflow the joints. ECP or GSF probably sell them cheaper.
Mercedes 230 E ( W123 ) fuel pump relay - Mr Fox
Hi There

Its a 1984, Automatic, saloon, I will look in all these places and hopefully it will be fairly obvious, guess it coul dhave been affected by being standing for a couple of weeks.

Mercedes 230 E ( W123 ) fuel pump relay - Peter D
You can often gently remove the cover off these type of relays and inspect the contacts for burning and if appropriate clean them with a specialist diamond spatula or some 1000 grit wet and dry blow out any loose particles and then polich clean with a douple up peice of white A4 paper inspect for cleanliness and try the relay back in its socket. Some of couse suffer coil failure and can not be repaired but a meter will show you that. Ohter of course have electronics wrapped around them and may be a challenge. Regards Peter
Mercedes 230 E ( W123 ) fuel pump relay - Aprilia
On these MB relays the relay itself is a little 'open frame' relay sitting on a PCB with a simple CR timing circuit (for 'priming') and a drive transistor. On the ones I have repaired the soldered joints have cracked where the PCB connects to the base pins. Reflowing the joints with a hot iron can cure the problem.
Mercedes 230 E ( W123 ) fuel pump relay - Peter D
Late yesterday repaired relay R30 from a Golf 1.6. Hairline crack around the connection from one of the spades to the PCB. This is a common problem due to the flow soldering technique not allowing the larger contacts to get hot enough to flow the soldered joint proberly. The owner of the car had spent £210 at a VW specialist garage chasing an intermittent engine shut down but to be fair to them they could not induce the fault however why they change the temp sensor God only knows. But then it happened whilst he was here and it was clear he had a power control problem and inspection of the associated relays revealed the problem and a good clean and reflow of the joint and all its OK. Regards Peter

Ask Honest John

Value my car