Tap operation on 1980 Westphalia Joker

[THE KESZTHELY KID]

Hola Amigo',

Jut spent an hour trying to get the tap to work on my recently acquired 1980 Westphalia Joker. The water tank is just over half full yet the LH Colum of LED's shows nothing whereas the RH Colum of LED's show Green but when the tap is turned on goes to Yellow. Even with he engine running.
Can anyone advise what I test to ensure a successful result 
Voltmeter at the ready 

TIA
Rick

[mioba]

You just turn it. a microswith in the tap turns on the pump in the water tank.
Either tap switch is dead or the water pump.
Easy all to identify with a meter, continuity, V, good grounds.
Enjoy the tinkering search the forum.

[davidoft1]

Wiggle the fuses by the drivers door