just thinking out loud, but if the issue is only that one pump, could you not put the cooling pump contactor coil through a normally open contact on seperate relay, with that relay coil being energised by the control circuit power, so the NO contact is made when the controls circuit is on, but drops out the coil to the coolant pump when the control is off, hence shutting it down. That way regardless of the state, the pump will only run (or be available) when you have control power on, or is there a need for it to run on ?