I have a 1987 Bmw 325E. Ever since I bought the car it has ran fine. However, on a trip coming home it just died on the highway. I checked over everything and finally discovered the fuel pumps aren't working. In the Haynes Manual, it says to check the main fuel relay first, then if it's okay to check the fuel pump relay. Where is the main fuel relay? I have checked the fuel pump relay and it works fine. However, the fuel pumps are not turning on. I checked the wiring connections to each one and cleaned them, but still are not working. I tried to check for shorts, but that would be a lot of work to track down all the wiring. Since they just suddenly stopped, isn't there something that I'm missing? Help!!

Sincerely,
Todd

I think i already answered that question on the cartalk board. White relay under a cover in front of the fuse panel is main relay. Cannot be replaced with one of another color because it is a dual output relay. Probably your pumps are bad, that is the usual cause of the problem.

I think i already answered that question on the cartalk board. White relay under a cover in front of the fuse panel is main relay. Cannot be replaced with one of another color because it is a dual output relay. Probably your pumps are bad, that is the usual cause of the problem.

That's for a newer car. My relays are parallel to the engine on the drivers side mounted atop the splashguard. There are 3. 1 is silver (to the front) and the 2nd 2 are blue Bosch. The middle one is a SDSP that goes to the fuel pumps. I haven't tested the pumps yet, but it's unlikely that both would go out at the same time. I figure it is a short from the relay to both pumps. Besides, there isn't power at either pump, so the assumption that both are bad is an unwise and expensive prediction. Replacing them now would be useless since there is no power there to operate them. Another suggestion would be appreciated.

ignore the relay colors! [different vender,different color]...the key is the wire colors conncting to them. of the three relays, the 5 pin one is the 'main relay' for the system, the other two are 4 pins and identical, the one with 2 green/purple wires coming off one terminal is for the pumps. testing: key off, the big RED wires on the 'main relay' are 'hot'...with the key on, the RED/WHITE wires MUST be 'hot', if not, replace the 'main relay' which is a common failure. to test the 'fuel pump' relay, the RED/WHITE wires will be hot with the key on [from the 'main relay' supply]. with the engine CRANKING the GREEN'PURPLE wires should be hot & the fuse [both sides] will be also. if one relay is bad, replace them both [due to age] WITH THE CORRECT ONES!....be sure to match up all the pin #'s EXACTLY...hope that helps

I appreciate the help! Actually, I thought it was a short after doing the testing that I did according to the Haynes Manual. I tested for power at the pumps as I went from the engine compartment back. Come to find out, the "Y" connector underneath the back seat had corroded away to split the wire to both fuel pumps. I rersoldered the connection and replaced the Bosch relay. Works like brand new, hehehe! Thanks again for all the advise!

Todd