If grounding the sender lead doesn't give a green LED, the common reason is
that the LM324N 12-pin DIP chip on that side has gone bad.  DigiKey has
them for USD 0.50 in singles.  Any electronic parts place should have
them.  For easy removal, clip the chip from its leads and remove them
individually.

https://www.digikey.com/product-detail/en/texas-instruments/LM324N/296-1391-5-ND/277627

Yrs,
d

On Fri, Jul 28, 2017 at 12:47 PM, gilles.turmel <gilles.turmel@sympatico.ca>
wrote:

> À friend of mine has an 86 Westfalia, no light is showing from the water
> tank level sensor. The sensor was changed, no lights. Anyone has a clue on
> the problem. Best regards.
>
>
> Envoyé de mon appareil Samsung de Bell via le réseau le plus vaste au pays.