Fuel pump. Low voltage. k1100

[Areshuan]

Hello !
The pump is healthy. It works perfectly when applying 12 volts directly to the pump or when using the fuel sender wires.
The voltage at the socket reads 13 v.  but when i connect it to the fuel sender socket it does this thing.  Voltage around 6 v. And erratic functioning.
I swtiched some relays and its the same story.

https://www.youtube.com/shorts/KeSQ57i2sj4

Any ideas?  Thank you

[Scott_]

Sounds like an issue with the "pass-thru" function of the fuel level sending unit assy that is mounted to the underside of the fuel tank.
It isn't common for this to fail, but it is not unheard of either.

I'd suggest looking for a good used one.

[Areshuan]

I change the fuel sender wires and  connectors. It works perfectly as shown in the video.
But as soon as I put it together with fuel i got the same problem.  I have no idea what to do next .

https://www.youtube.com/shorts/8o_9Geh8PWI

[Areshuan]

It was a loose ground cable !

[Laitch]