The old pigtail has to be cut off. The new pigtail should have a pigtail that has a connector that plugs into the new pump on one end and four unstripped wires on the other end. You need to strip the old wires on your truck where you cut off the old connector and strip the new wires on the other end of the new connector back about 3/4 if an inch. Join the appropriate wires together per the instructions provided with the new pump which will also tell you where to put the purple wire, and twist them together individually. Either use heat shrinkable tubing or electrical tape to each wire you joined together. after each individual wire has been taped, then tape them all together to keep out any road water and grime.