Power windows have become the norm on modern vehicles and while electronically controlled window regulators provide fingertip control of the windows, a window regulator can fail suddenly (and unexpectedly) for any number of reasons. Below we discuss how window regulators work, symptoms of faulty window regulators, what you can expect when you have to replace one, and our recommendations for the best window regulator brands.
Function Of Window Regulators
Put simply, the purpose of a window regulator is to control the up-and-down movement of a vehicle’s window at the push of a button, either from a window switch mounted on the door or in the center console.
However, and regardless of the actual design, modern window regulators are complex mechanisms that incorporate many interconnected components, such as pulleys, idler arms, gears, cables, slides, and others that are all controlled by a DC motor via a control switch.
Moreover, window regulator motors are in turn controlled by complex electronics that include limit switches, load-sensing circuits, overload sensors, auto-reverse functions and other features that prevent situations where a hand or other body part can be pinched between the moving window and the door/window frame.
As a practical matter, there are two main window regulator designs in use today. One design is based on power-driven gears that produce a movement of the window, while the other type is based on a cable that is wound around small, winch-like device. In the latter design, the cable can be wound around the winch in two directions, depending on the direction of rotation of the window motor. In either case, winding the cable around the motor-driven winch produces movement of the window.
It should be noted that window regulators generally do not require any maintenance, adjustments, or other routine servicing during their lives. Window regulators usually provide many years of reliable service, but when they do fail, the entire regulator must usually be replaced as an assembly, since window regulators are not typically easily repairable. We should also note that there are some window regulator designs where the electric motor can be replaced standalone, but only if it is not integrated into the window regulator assembly.
Common Symptoms Of Faulty Window Regulators
While window regulators can and do fail suddenly and/or unexpectedly, most designs will usually provide a fair amount of advance warning that something is amiss. These symptoms usually include the following:
Slow Window Movement
This can happen during opening or closing, and is usually a sign that the mechanism is sticking or binding due to lack of lubrication on moving parts. In some cases though, the rails that guide the glass within the door may also move out of alignment or become sticky.
Window Does Not Open And/Or Close Fully
The most common cause of this is defective electronics (limit switches) in the window’s control circuits. Most windows are controlled by two switches: one located on the same door as the wndow and one located on the driver’s door. If the issue only manifests when one of the two switches is actuated, the problem is likely the switch and not in the regulator’s electronics.
However, in some cases, excessive wear in the regulator’s moving parts can force the glass out of alignment with the rails it slides in, which can cause the glass to bind or stick at certain points in its travel.
Window Only Moves One Direction
While this is a common problem on power windows, faulty window regulators are seldom the cause; it is more common for defective control switches to produce this symptom. Nonetheless, this can occasionally be due to a faulty window regulator.
This is fairly common in areas that have harsh winters, where it is cold enough for windows to freeze into their rails. When a frozen window is opened, the force of the downward movement produced by the regulator can cause the regulator to separate from the glass when regulator’s attachment points break. In some cases, the glass can be reattached, but in most cases, the window regulator must be replaced due to this damage.
Noise When Operating Window
This usually occurs on gear-driven regulators, and replacement of the regulator is usually the only reliable, long-term remedy. This manifests as a mechanical grinding, clicking, or clunking noise when operating the window.
Replacing A Window Regulator
Window regulators are generally not expensive, and replacing them is relatively straightforward. That said, they do take some finessing as often times they are located in a relatively confined space within your door.
Note: The example steps below are intended for general informational purposes solely to help give you an idea of project difficulty and tools required. As all cars are engineered differently, repair procedures and safety hazards vary from vehicle to vehicle. To ensure that you have a vehicle specific repair procedure and an exhaustive list of potential safety hazards, we advise you reference a factory service manual for your vehicle. Similarly, referencing a repair manual such as Chilton or Haynes might serve as a less expensive alternative.
Step 1 – Temporarily secure the glass to the doorframe to prevent it from falling into the door cavity when you remove the old regulator. A low residue tape or similar can be used, but take care to choose tape that will not damage your window or car’s paint.
Step 2 – Remove the door panel carefully, taking necessary precautions not to damage any clips or the door panel itself. A small screwdriver set may be helpful here. Pay close attention to the wiring connected to your door panel and unclip any connectors to avoid damage to any of the wires. Remove the inner dust seal from the door. As this part can be fragile and relatively inexpensive, it is wise to have a new one on hand.
Step 3 – Locate all fasteners, and use appropriate tools to remove them such as a set of deep sockets and a flex head ratchet. Note that depending on the vehicle, you may have to lower the glass somewhat to be able to detach the glass from the regulator. Remove the old regulator from the door, but take great care not to let the glass drop down into the door cavity as it could take a great deal of effort to fit the glass back into its rails again (or possibly cause injury if it drops onto your hand).
Step 4 – Install the new regulator in the exact reverse order of removal of the old unit, but make sure you insert all fasteners. Often times you can use the marks left by previous fasteners in order to index the regulator properly and limit the amount that you have to adjust to achieve smooth operation. We suggest that you take care to avoid overtightening fasteners by using a torque wrench to torque the fasteners to factory spec (see our torque wrench buyer’s guide here).
Step 5 – Once you are satisfied with the placement of the regulator, we suggest testing the window. You can use a window switch from the door panel. Make sure the window goes up and down smoothly without any grinding or popping. After testing the window, fit the new dust seal, and reinstall the door panel including the electrical connectors. Also, make sure that all door panel clips are aligned with their holes in the door frame before pressing them into place to avoid breaking clips, or worse, the door panel.
Best Window Regulator Brands
Dorman makes a wide variety of auto parts, including window regulators. Dorman makes OEM quality parts, and their window regulators are no exception. When it comes to value, Dorman’s window regulators perform well but certainly don’t break the bank from a cost standpoint. As such, you can replace your window regulator for a reasonable cost and expect it to last. Overall, if you choose to replace your window regulator with a Dorman part, we are confident that you will be satisfied!
AC Delco window regulators are designed to be direct functional replacements for original equipment, and include all the latest engineering innovations and upgrades. In practice, this means that a replacement AC Delco window regulator will provide smooth power window operation that will last many years. Their parts are high quality, tested for durability and are reasonable from a cost perspective. Overall, we think you’ll be happy if you choose to install an AC Delco window regulator for your next replacement project.