Check the Fluid
First, check that the windshield washer bottle has fluid and that the fluid is free from debris or algae growth. If the fluid is contaminated, the washer reservoir should be drained and cleaned.
Open the hood and locate the windshield washer reservoir. On some vehicles, it may be located under the front fender or bumper. The owner's manual will often tell you the location of the washer reservoir.
A Blown Fuse?
Do you hear the windshield washer pump operate when you use the windshield washers? It may help to have a friend operate the washer pump while you listen. If the pump is not heard, check the fuse panel to see if there is a blown fuse. (Note: There may be more than one windshield washer pump if your vehicle has a head light or rear windshield washer system.) If it is not clearly marked on the fuse box cover, you may need the owner's manual or an electrical diagram to determine which fuse protects the washer system. If no fuses are found to be blown—and the washer pump makes no noise when the switch is activated—one of the components may be defective (the switch, washer pump, relay if equipped, etc). Don't worry yet—let's pretend that your hearing might not be what it used to be and continue with the checks that don't rely on hearing.
A Leak? A Weak Pump?
If the washer pump appears to operate, fill the reservoir and inspect for any leaks, perhaps from a defective reservoir or seals. Then activate the washers and inspect the system for leaks from the hoses that carry washer fluid to the washer nozzles or jets. Many times, heat from the engine compartment deteriorates the hoses. Also, rodents have been known to chew through the hoses. If no leaks are found, disconnect the washer tube carrying fluid to the washer nozzles—there is usually a convenient junction around the hood hinge. Operate the windshield washers again and see if fluid squirts out of the hose with sufficient volume and pressure. If not, the pump may be weak or the washer fluid is facing a restriction in the lines due to dirt or a kink in the washer hose.
If washer fluid does squirt out of the washer hose, you may have a restriction in the washer nozzles themselves. This restriction may be caused by contamination that has entered through the washer reservoir or the washer nozzles might be blocked from car wax that has hardened from the last time you waxed your car.
If it is wax or blocked from the top side of the nozzle, you can use a small needle to clear the washer jet. You may need to use compressed air to clear stubborn debris that has lodged in the washer nozzles.