A window regulator generally works the same, regardless of whether it's in a manual or automatic window system. It's the part that transforms the rotating motion of the motor into the vertical movement that allows you to raise or lower the glass. When it breaks down, you'll have to remove your door panel and poke around inside. However, a bad regulator isn't the only reason for a faulty window. Knowing the differences can save you time, effort, and money. Here's a short guide you can refer to when trying to diagnose the problem:
For manual windows, it's an open and shut case; the window regulator and crank are all one piece. Open the door panel and check for loose, rusted, or worn moving parts in the regulator.
Age or obstructions to the mechanism can easily blow a fuse since window regulators use a lot of power. If pushing down on the button does nothing at all (ie. no sounds from the motor, glass isn't "struggling" to move), then you're looking at an electrical problem. Referring to your owner's guide, open the fuse box and check it out. If the fuse is in working condition and the window still isn't operational, grab a 12v test light and a schematic of your vehicle's electrical system. Test the wiring from the fuse to the switch, then from the switch to the motor. If, along the way, you find a connector that's loose or corroded, you've found what's blocking the voltage. Another possibility is a bad switch. For instance, if the passenger door's window can be moved by the button on the passenger door but not by the button on the driver's door.
This is a sure sign of a bad regulator, or at least something physically stopping it from doing its job. Check for any obstructions or things that could increase the friction between the gasket and the glass. It doesn't take much added friction to make it too much for the regulator to move the window. As for the regulator itself, be on the lookout for damaged, disconnected, and missing parts. Jammed or sticky cables, broken or missing bushings, and corroded parts are all possible symptoms of an ailing window regulator.