There is not a separate motor for the wiper fluid pump. It gets its motive force from a cam driven by the windshield wipers themselves. I would divide the problem in two. Take a look at the wiring diagram. I would separately engage the solenoid with a set of temporary jumpers, you should here a click as it gets engaged. I would do this first with the wipers off. If you don't hear anything the solenoid could be bad. If it engages, I would try again with the wipers on. If everything is engaging, I would think either the flapper valve or the diaphragm is bad. Also you can pull the cover to inspect the workings. Its pretty simple when you how it is designed.