Windshield washer pump wasn't working, but it was receiving voltage and getting warm. I pulled it and shook it - no change. I blew it out - no change. Figuring there was no harm in trying, I jumpered it to a battery charger and fed it various levels of power from 2 amps to 10 amps. It made some grinding noises at first, but finally at 10 amps it broke free. I gave it 2 amps until it ran smoothly again, and even reversed polarity for a moment(to try and get any grit out). Reinstalled it and now it works perfectly (but for how long I have no idea). I love it when stuff like this actually works...