Tap not working and water tank control panel

[MickyTwoPints]

I've recently had the water tank symbol on the control panel flashing to indicate there's an issue with the sensor and now the tap has stopped working. I am in no way technically minded but looking at the top of the water tank, I have three wires, none of which are connected to anything. Does anyone know which of the wires in the photo should go where? Hoping that might fix at least one of the issues.

Thanks

 

[MickyTwoPints]

OK, progress has been made... I found another loose wire. Two seemed to come from the battery and two went elsewhere so I attached the ones that fit together and now the tap works and the error on the control panel is no longer flashing. The water water doesn't show as having any water in it though, even though I've put about 15 litres in