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Thread: Fuel pump relay part number

  1. #1
    Join Date
    Dec 2011
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    Littleton, CO
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    Fuel pump relay part number

    Sitting in a parking lot and my 07 M400 won't start. No fuel pump sound when I push button on keychain or when I turn the key. I called turbohoses and they said my fuel pump relay is probably shot. I guess this is a common problem. The relay is in a terrible location to get to. Behind firewall, in the engine compartment, right above the battery behind velcro'd in heat shield.

    Has anyone else had to replace it and what is the part number. Can this be bought at a Ford dealership. I'm sure (and hope) it's just a standard Ford relay that can be easily gotten.

    Thank you.

  2. #2
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    Dec 2011
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    California
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    The fuel pump relay is a common Bosch-type automotive relay - you should be able to get one at just about any auto parts store, or even Radio Shack. If you're in a pinch, you can pull one of the relays out of the electrical panel in the passenger's footwell (The horn relay (Relay L) is a good one...) and use that to get you going.

    Also, check the four fuses in the rear fusebox near the relays, and the two-pin white connector that should be in the harness near the relays/rear fusebox. If your car has had the fuel pump wiring mod, there should be another fuse (or maybe a thermal circuit breaker) and relay associated with that. You'll have to track that down and find it yourself, since there's no real standardized location for these parts.

  3. #3
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    Dec 2011
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    Littleton, CO
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    Thanks Jim!

    I do have the upgraded fuel pump harness. I guess from late 06 on, all M400's had the upgraded. The fuse is right by the solenoid like all the pictures show. Thanks for the suggestion using the horn relay. I'll put that in as a test relay to see of it's the fuel pump relay

  4. #4
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    Dec 2011
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    Littleton, CO
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    No luck! I took the fuel pump relay out, put it where the horn relay goes and the horn worked. Took the horn relay out, put it where the fuel pump relay goes and still no fuel pump. I checked the 4 fuses right above the fuel pump relay and they are all o.k. I also checked the 15 amp fuse that is in the upgraded fuel pump harness that is right next to the solenoid and it was o.k.

    What should I try next?

    When I turn the key to where it should be to push the fuel pump starter button on the keychain, I hear a little humming, clicking and the battery and oil light come and stay on. Starter will turn over but absolutely no humming from the fuel pump. Is there a way of checking the fuel pump itself. Thank you.

  5. #5
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    Dec 2011
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    Littleton, CO
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    I was at best buy when all of this happened. I had a bunch people that wanted to see the car so I opened up the rear clam. I closed it, got in and no fuel pump humming. Is there anything from opening and closing the rear clam that could have caused this problem. I doubt it, but thought I'd ask.

    Thank you.

  6. #6
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    Dec 2011
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    It seems that your fuel pump is bad.

    Check your PM box.

    Noblerine

  7. #7
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    Dec 2011
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    Littleton, CO
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    Where the fuel pump and filter are, there is a Spal (brand name) relay that all the wires that come into and out of it go to the fuel pump. Looking online I saw something exactky the same that is a engine cut connection relay. Could this be tied into the immobolizer and locking system and I did something weird when locking the car and this has frozen out the fuel pump. Do you guys have a relay in where the fuel pump and filter are?

  8. #8
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    Remove the imobilizer fuse and see this unlocks the fuel pump.

  9. #9
    Join Date
    Dec 2011
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    California
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    In a stock Noble with the fuel pump wiring mod, there are two relays that get power to the fuel pump. The first relay is part of the engine harness - it turns power on/off to the white two-pin connector in the engine bay, near the rear fuse panel. That two-pin connector used to feed power to the fuel pump. With the fuel pump wiring mod, that connector now triggers the second relay, which supplies power directly from the battery to the fuel pump. Depending on who did the fuel pump wiring mod and what kit (if any) they used, I've seen that second relay in all sorts of different locations. It could be mounted with the rest of the rear relays, it could be on the frame rail near the solenoid, or it could even be in the side pod with the fuel pump/filter. If this fuel pump wiring mod was actually done by 1G/Rossion, they probably used the Snakebite harness, which puts the relay on the battery side of the car, so the relay that you see over in the fuel pump area is something that was added on along the way - maybe part of a security system or a hidden-switch type of disabler. Does the wire from the 15amp fuse near the solenoid go to a nearby relay, or does it head straight over towards the fuel pump? If you can find the two-pin connector, see if there are two wires coming in/going out, or if there are two wires coming in and a single wire on one side of the connector coming out. This will give me a clue about the purpose of the relay over near the fuel pump, and what controls it. While you're at it, if you find the two-pin connector, try disconnecting/reconnecting it a few times - I've seen these contacts become dirty/corroded enough to make the fuel pump not turn on.

    Also, if the Spal relay is a standard Bosch-type relay, try replacing it with your horn relay. If that doesn't work, you'll probably need a test jumper (a wire with a male 1/4" tab connector on both ends) or a test light or multimeter to go much further...

  10. #10
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    Dec 2011
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    I took the imobilizer relay out and tried to start the car, no fuel pump whine. I took the horn relay out and put it where the imobilizer relay is in the fuel pump/filter area and still no fuel pump whine. I've checked the fuel pump relay, switched it out with the horn relay, the horn works fine so the fuel pump relay must be working fine. I put the horn relay in the fuel pump relay spot, and still no fuel pump. I checked the 4 fuses above the relays and the 15 amp fuse in the upgraded fuel pump harness that is right next to the solenoid and all of those are fine. Is there a way to see if the fuel pump is getting power. on the 044 there are two post, one blue and one red. When I turn the key on, I would think there should be some volts there. How do I check that. If the fuel pump is getting power and not turning on, I would think it's bad.

    Thanks for all your help, this is very frustrating!!

    I put some pictures of my set-up on the other forum, I can't get them on here. Please look and offer any suggestions.
    Attached Images Attached Images

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