Very common problem. The pumps are simply bad. I pulled mine and took it into the workshop and hit it with 12 volts. Lots of sparks, but no spinning!
Advanced Auto has a workable alternative for about 20 bucks. Pull yours and take it in so they can match it. Pep Boys does not stock anything that will work. Other retailers might. The pump is provided by Thor, not the chassis manufacturer!
You can get a replacement from Thor, but a web-search says that's a crap shoot. Half the replacements are bad too.