Wiring & Plumbing Query Re: thread 87459

Steve, the usual setup is from the tank to the pump to the tap,when you turn the tap ON in the van the pump senses low pressure and begins to pump until you turn the tap OFF. You need to make your front tap connection Tpiece somewhere between the pump and the van tap so the pump can detect low pressure when you turn the front tap on. The pump works on 12v usually, now, if you lose or split the hose on the tap side of the pump it will sense low pressure and pump your tank dry, I have put a switch at the van battery to switch the pump off when travelling,I split a hose on the track from Cameron Corner to the Strez, we had no water when we camped . Regards Keith.

HereIt sounds like you have an inline pump that is activated by a switch that is built into the sink tap.
Find the wires that lead to this tap and insert another switch into this line so that it turns the pump on and off independently in this way you would have to turn the tap on then turn the switch on/off.
It would be better if you purchased another pump that is pressure activated.
Like this one above.