It's a common problem with the helix speedo that the fuel gauge led have one to 3 bad bars that don't light up with age. With these led being inside the whole unit it seem like there s no way to fix it. I m wondering if its possible to just wire up a set of gauges and a generic speedo to take there places. It's no worth trying to find an oem unit to replace it because it might have the same problem
It might be worthwhile to disassemble, spray with de-oxit, then reseat all of the multiconnectors. Those LCD segments are usually pretty reliable. If it is easier to get at the fuel tank sending unit, disconnect the leads, remove and check the potientiometer with a vom to make sure it is signalling the lcd fuel gauge. Would be worh a look before trying an add-on device.
There is a chinese variant of the Helix that uses an analog gauge set in place of the costly digital one. Looks like a bolt-in replacement! Hoenstly though, these are usually pretty reliable... I'd disassemble it and check for corrosion or a loose terminal. What year is your Helix?