Seeking the Elusive Electrical Problem. Many times electrical problems are the most elusive, because they can occur intermittently. For example, the car engine may not work properly, but only after the engine warms up. Or the ignition works randomly. Perhaps the engine cuts out without notice while cruising down the highway. Then again, your car might have a faulty alternator or a defective wire.
Attach the leads of the multi-meter to where the electrical wires come into the motor. Again, set it to DC volts and it should read 12 volts. Look for any interrupted voltage caused by a loose connector or corrosion. If there are any loose or corroded connections in the circuit they will disrupt the signal and cause your window to malfunction. Fix the connector or corroded areas. Push any connectors or wiring harnesses together tightly, and clean any corrosion away with a wire brush or similar tool. Test the window again. If your problem was in the circuitry and is now fixed, then your window should freely roll up and down without any restrictions or delays.
If the battery terminals are clean and tight, then the next item to check is drive belt tension. If the belt which drives the alternator is too loose, then the alternator will not produce enough electrical current to keep up with demand. Many modern vehicles utilize a single belt which drives the alternator and other accessories. This system usually also has an automatic belt tensioner which always maintains correct tension and is not adjustable. If your vehicle uses a wide, multigrooved or so-called "Serpentine" belt to drive the alternator, then it likely also has an automatic tensioning device.
Battery: this invention has made the complete car electric system possible. From the old heavy and unreliable ones to today's modern batteries, it's something that a car can't go without. In the invention of the batteries lay the seeds of today's modern electric-cars. Spark plug: today it's an usual item in car mechanics. But think of the people that invented it!! Lighting the fuel-air mix with an electric spark, simply amassing. How great it is, proves the fact that the principle is unchanged ever since. Every invention on the car has it's purpose and, in mechanical terms,it's own beauty. Ranking of this kind doesn't neglect all of the other marvels on the car, on the contrary. The genius in these 5 inventions is that they stayed basically unchanged for all of these years giving the driver comfort, safety and reliability