Windshield wipers still not working

bought a “new” wiper motor or whole drop in unit–supposed to work. have new wiper switch. have hot in the plug to inside switch. washer motor worked for a few tries and then quit. with wiper switch “on” there is no hot in the firewall plug. tried switch in all positions and still no hot in firewall plug. fuse good, battery hot… i am perplexed. michael 85 xjs