In modern cars, the windshield washer pump comes as one unit with a small electric motor. Typically, the windshield washer pump is installed in the lower portion of the windshield washer fluid tank (reservoir). Windshield washer pumpWindshield washer pump (motor) is located at the bottom of the windshield washer fluid tank.In most cars, the windshield washer tank is located behind the front bumper,How it works: When you operate the washer with the switch, it sends the signal to the control module (e.g. BCM) that, through the relay, operates the windshield washer pump. The pump pumps the windshield washer fluid through the hoses that are connected to the washer jets.One of the common problems is when the windshield washer pump electric motor fails and doesn't run when activated by the switch. In some cases, the pump fails, so you can hear the motor running when the washer switch is operated, but the washer fluid doesn't spray. A bad windshield washer pump (motor) must be replaced.