How to troubleshoot a windshield washer pump. Most vehicles have a windshield washer reservoir located under the hood. It's going to have a cap that either says windshield washer fluid or have a picture of a windshield washer spritzer. Located in the reservoir usually on the bottom with a grommet, is the windshield washer pump itself. This is an example of a typical windshield washer pump. This part goes into the windshield washer reservoir and this part goes to the hose that runs to the actual spritzers. To test a windshield washer pump, you want to find a good 12 volt source, in this case we're going to use the battery in the vehicle that we're checking and we just hook up some leads and then you want to attach your negative lead to your ground and your positive lead to your positive and you should hear the pump turn over and you should feel air coming out of the output side of the pump. If the pump doesn't turn over, then obviously the pump itself has failed. However if the pump does turn over, the next thing to check would be the wiring harness at the reservoir itself and the best way to check that is with a multimeter. You need to have an assistant help you, you put the connections of the multimeter onto the connector that goes to the fuel pump and have your assistant put the windshield washers sprayer switch in the on position and you should get 12 volts here. If you don't, then you're not getting voltage at the pump and it could be a fuse or a wiring harness issue.