Peter see below for the complexity of fuel level system on a 3.7 Roadster.

[Linked Image]

It's likely whilst different yours will have some commonality with above. Particularly note the two ground connections at the bottom serving the fuel level unit. They likely carry very small currents so would be susceptible to any connection resistance. They are not shared because the tiny current in one could affect the other. If you can find similar on yours re-make those connections or indeed any associated ground connections you find.

Break and re-make any connector you find in the area as well.


Richard

2018 Roadster 3.7
1966 Land Rover S2a 88
2024 Royal Enfield Guerrilla 450
1945 Guzzi Airone