series 2a fuel gauge

just rewiring my series 2a 109. fitted a new tank sender unit . the gauge reads full when the sender is at the bottom and as I lift it goes to full. tried another gauge and this behaves the same . it was never fitted with a voltage stabaliser but I have tried it with and without. if I reverse the terminals an tha gauge then it goes to full and stays there. even tried it all out on the bench and I cannot see the problem unless its the sender and gauge incompatable. is there more than 1 sender unit type ?. I have the universal britpart sender.

Sounds like the same problem I had with my series 2. It seemed like the polarity on the sender was wrong but as its negative earth there was nothing I could do with it except cobble together the old one and re-use it.
That was a blue box one as well.

Of course there might be another explanation ....I'd be interested to hear what anyone else thinks.

decided to fit a series 3 gauge and see if that cures it.

In the end the float moves a wiper over a curved resistor. You can solder the wires the other way or turn it round and reverse the float arm so it moves the opposite way when the float goes up.

The Series 3 fuel gauge works with a sender where the resistance is low when the tank is full and high when the tank is empty. It may be that the Ser 2 gauge works the other way round i.e. sender resistance high = tank full. There seem to be two different standards and it's possible Land-Rover moved from one to the other at the end of Ser2 production?
As per Rob's post, you might be able to modify the sender to work "upside down". Does the Ser3 gauge work correctly?

have not got the series 3 gauge yet but will try it when it arrives.

fitted the series 3 gauge and voltage stabiliser and all works as should