The test procedure is quite simple. Set the meter to read DC volts, and set the correct range if needed. Some meters will select the correct range automatically. Nearly all meters will come with instructions on how to set them to read DC volts. Next, connect the meter across the vehicle battery, positive (+) to positive (+) and negative (-) to negative (-). With the engine running at a moderate idle - say 1200 to 1500 RPM, the meter should read approximately 13.8 to 14.8 volts and be steady. If the reading is substantially outside these figures and all other items mentioned have been tested and verified good, then the alternator is likely defective.
Replacing Your Window Motor or Regulator: Remove the door panel. This task will vary from car to car, but typically you will have to remove some screws around the middle of the panel (such as inside the door pull) and then use a prying tool around the outside to pop out the clips on the perimeter. Sometimes you may have to remove things such as weather-stripping or door moldings as well.
Replacing a Faulty Switch: Locate the window switch panel. This is the button used to operate your window. It is almost always on the door, however, they are rarely found on the center console. Remove the window switch panel. Be careful not to scratch up the door panel while removing the window switch, as it often requires prying. Using a shop rag or piece of cardboard under your prying tool can help. Unplug the wiring connectors from the switch. You will need to test these connectors to make sure that they are providing the appropriate 12 volts to your switch.
A good thing with battery checking and trouble shooting is that you need very little technical equipment. All you need is a good, old Digital Volt Ohm Meter and a charger for the battery. Each auto battery manufacturer uses a certain color in the battery 'eye' which tells whether a charge is needed. This is a fast and easy way to alert you for re-charging. Check out your battery manufacturer's specification of the 'eye' and everything associated with it.