Nissan Patrol 4x4 (Africa)

I'll try get a photo tonight and post it here

Elmar, there is a posability that your water indicator that screws into the filter is faulty. To test this you can simply unplug the wire and just drive if like that for a week or so to see if the light comes on again. Its a normal open system so if the light comes on again even with it plugged out you have a short somewhere on the wiring, if it stais off I would say the indicator is busted

Coolbeans I'll do so thanks Michael