If the reason your diverter moves slowly is voltage drop caused by the long battery power run(from bat to dash and back to pump assembly) then this product should help immensely.Banderlog Diverter Power Relay (http://www.banderlog.com/products/po...owerRelay.html)
There was a recent thread on this subject.
EDIT: Make sure the ground circuit is also in good shape. No loose connections or connections to painted surfaces. A voltage drop here will have the same detrimental effect as voltage drop on the power side of the circuit.