Fuel pump hot wire

[RandyM]

Hi all, it seems my fuel pump hot wire (grn /vio) is shorted to ground somewhere between the combo relay and the fuel pumps. With combo relay Unplugged and fuel pump disconnected,probing wire side of connectors at c/r end and both pumps shows continuity to chassis. Has anyone experienced this and can point me to the location I should look first please. Under the back seat is where I’d start.

Thanks

[Mike W.]

What sort of resistance? Remember the fuel pump, thru it's windings, does bridge hot and ground, probably at something like 4 ohms.

Troubleshooting. First step, disconnect both pumps and see what you get then.

[RandyM]

Thanks for the reply Mike, yes I thought about it a bit and got things sorted properly. The new Bosch pump is way noisier than the old one which I could barely hear, I think it was original.

[Lock]

You can quieten the external pump a little with some rubber or foam between the pump and pump bracket. The rubber mounts for the assembly have probably hardened up.
Sometimes the pumps will be loud if the suction pipe is bent or kinked as it's struggling to draw fuel and can starve the engine under acceleration, so make sure that's not the cause of the noise. You shouldn't be able to hear it in the car with engine idling- if you can clearly hear it whining or howling, something may be wrong. Or you have a dog in the back seat.