Fuel Gauge voltage regulator required?

[mrsmelt73]

Evening all, We have a cross over bay and have fitted a new tube type fuel sender unit. It works but is not dead accurate. When the headlamps are turned on the gauge goes to full first then back to zero, where it stays whilst the lights are on. Might an aftermarket voltage regulator (as sold by heritage or similar) sort this, or has anybody got any experience of a similar issue?
Thanks,
Nearly on the road but not quite.

 

[sparkywig]

That's an earthing issue, check the ground connections on the back of the instrument pod.

 

[67panel]

Well the fuel gauge is wired with an ign feed then the other side goes to tank unit that should have an earth (brown) wire to ground. Sounds to me like the ign feed is interrupted when the lights are turned on? Check the light circuit and the fuel gauge is wired correctly.