What you should know:

The jets are plastic nozzles that are found right at or near the middle of your hood. These nozzles spray the windshield washing solution at varying levels of your driving speed. So proper alignment of these nozzles is absolutely important for the system to work.

A properly aligned windshield washer jet lets you to quickly remove mud and other impediments that would normally have been stuck on your windshield. Some of the signs that may make you think that the jets are not working may actually be because dirt, ice and other objects that may clog up the nozzle. Also if you use water in the windshield washer reservoir in a temperature that is below freezing, your entire windshield washer system may not work properly and that will include your jets.

Bear in mind:

The jets are the one components of your windshields cleaning system that are totally exposed to the elements. Ice, dirt, leaves, wax, and other objects can easily clog them up.
The jets that compose your windshield washer system are usually made out of plastic. These plastic jets also have nozzles on their very back that spray the windshield washer solution onto your windshield, and it doesn’t take much for these nozzles to have an object that dislodges them from their proper position. Older cars in particular can have the washer jets misaligned because of the wearing out of glue and other fasteners that keep the jets in their proper position.
Recommendation:

If the nozzles on your jets seem to be spraying in the wrong direction, or not spraying at all, the jets may have to be adjusted. However this can also be because of the deterioration of the washer tubes or even a windshield washer reservoir that requires replacement. If your washer jets won’t adequately clean your windshield glass, have an expert inspect the entire cleaning system. This way you can have the source of the system quickly identified and repaired. For most vehicles, the cost of changing your washer tubes, jets, and other related parts is very reasonable. So bear that in mind.

What are the common signs indicating you have to adjust the windshield washer jets?

Water spraying onto areas that are nowhere near the front of your windshield
The nozzle of the jets focusing the wrong direction.
Looseness of the washer jets. The ability to easily move the jets from their proper place.
How important is this service?

Vision is one thing you should not take for granted when it comes to your daily driving. In the case of windshield washer jets, you’re adjusting a component that isn’t costly and can make a world of difference when it comes to safety. If you notice that the washer jets are not spraying your fluid where it needs to go, then invest in a proper check.
see more:http://www.automobileglobe.com/how-to-adjust-windshield-washer-jets/