What is the screen washer/what does it do?
Windscreen washers are a simple but effective way of cleaning the windscreen enabling the driver to have a clear view front and rear. They are compulsory on any car with a fixed (i.e. non-opening) windscreen. A windscreen washer motor drives a pump which forces water from a reservoir through a series of tubes leading to the washer jets which squirt water onto the screen. This water combined with the wiper blades action effectively washes and cleans the windscreen.
Getting into the details of the screen washer
The screen washer reservoir is usually found in the front engine compartment. It is most commonly a moulded plastic bottle which will serve both front and rear screens. The motor and pump sit with the bottle and are activated by the driver with a lever on the steering column. The washer jets, usually two per screen, are situated externally and below the screen. These can be angled by the driver to maximise efficient washing of the screen.
Although clean water will effectively clean the screen there are many brands of screen wash available which, when added to the screen wash reservoir, will aid the cleaning process.
What if something goes wrong with the screen washer?
Common faults are failure of the motor/pump (water does not leave the reservoir), leaks in the plastic tubing that connects the reservoir to the washer jets, or the jets themselves being blocked and therefore unable to squirt water onto the windscreen.