Few situations are as unbearable as having to deal with a car window that won’t roll up. What would otherwise be a normal day is often ruined when you are forced to worry about the slightest chance of rain or fear a violent return home.
If you are currently facing a similar problem, you are definitely not alone. Window-related failures are quite common and leave thousands of drivers shaking their heads in dismay in any given year.
Read on to learn more about what causes window functionality issues and what to do when your window goes dark but won’t open.
How do electric windows work?
Power window systems combine the use of mechanical and electrical components to facilitate the up-and-down movement of the vehicle’s windows.
A window switch directs power to a vehicle’s power window motor, which drives the controller assembly. A power window converts the rotary motion of a power window motor into power window movement.
Power windows come in two different forms. The first of these two forms is the parallel (gear-driven) governor, which cuts off when in motion, like a scissor jack. As a window motor, it rotates a series of crank gears, which causes the controller to vibrate. As a result, an upward thrust occurs.
Recently, many vehicles have begun to use a drive-by-wire system. This system winds a cable through a series of pulleys, which are driven by the system’s power window motor.
In operation, this cable is pulled back and forth to raise and lower the glass to which it is attached.
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Causes (and solutions) of power window failures
Here are some of the most common power window faults, along with descriptions of what to do when each one occurs.
#1 – No Circuit Power
For a power window regulator assembly to work, it must receive sufficient power. This power is derived from a vehicle’s battery and is almost always routed through a fuse or circuit breaker, as well as a relay.
If power to this circuit is interrupted, any manipulation of the window switch will not raise or lower the window switch. A power window switch must first receive power before it can be distributed downstream to the backup power window motor.
How to fix
To resolve the problem of window circuit power loss, it will be necessary to use a reliable test light. With the corresponding door panel removed, check if power is supplied to the input side of your vehicle’s window switch. If your test light does not come on, locate the fuse through which this power is routed.
In some cases, each window will operate in a circuit. However, most vehicles spread this power distribution across multiple circuits. In many cases, the driver’s side window and the passenger’s side window of a vehicle will be fused separately from its rear windows.
In many cases, you will locate a blown fuse or a tripped circuit breaker. This is often the result of aging window motors, which have begun to draw too much amperage during operation.
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#2 – Replace a faulty window
Another common power window circuit fault is the power window switch system. Over time, the internal contacts of the switch begin to deteriorate, making it impossible to establish continuity when the switch is manipulated.
A significant number of power window system failures involve faulty switches. However, replacement is not recommended until such a condition can be verified.
How to fix
When attempting to diagnose a faulty window switch, the switch unit must be removed from its corresponding door panel. A test light or multimeter will also be needed to obtain a diagnosis.
First, confirm that your window switch has power. Your test light should turn on when power is detected, if it is properly grounded. Alternatively, more than 12 volts should be noted on the circuit wire supply voltage using a multimeter.
If incoming power is detected, repeat this process while checking for power at the output switch, with the switch depressed. If no power comes out of the socket side of the window switch, a replacement will be needed. However, looking at the power output, additional testing will be required at the point of connection to the system’s window motor.
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#3 – Faulty Window Motor
Sometimes the window regulator motor fails, in most cases due to a degraded internal circuit. When this happens, your window will likely stop working both ways, leaving you in a bind.
Slow or noisy window motor operation often serves as a reliable indicator of the unit’s overall health. If a window motor is installed correctly and runs at full voltage but runs at a snail’s pace, it should be considered suspicious.
How to fix
Fortunately, diagnosing a faulty power window motor is relatively simple. To begin this process, remove the panel inside your door. Next, locate the electrical pigtail that corresponds to the offending window regulator motor. Unplug the associated outlet and check for power and ground on the harness side of that connection while depressing the window switch.
If power and ground are present, your power window motor is defective and needs to be replaced. The difficulty of this job varies from one make and model of vehicle to another.
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#4 – Damaged window regulator
Like window motors, drivers are prone to failure over time. Over time, the mechanical components of a controller begin to fatigue, often resulting in irreversible damage. Either way, a faulty window regulator is usually fairly easy to diagnose.
If you have a vehicle window that won’t stay up, appears tilted to one side, or has fallen from its frame, a faulty window regulator is almost certainly to blame.
How to fix
Diagnosing a faulty window regulator is a matter of visual inspection. Removing the interior door panel provides a fairly clear view of this unit.
Carefully inspect the pivot points, brackets, cables, and regulator window clamps for any signs of damage or fatigue. If an irregularity is found, replacement is recommended.
Replacing a window regulator can be quite a challenge, depending on the particular model of vehicle being repaired. This procedure can range from simple to very tedious. If in doubt, always seek professional advice.
Read also: 4 ways to cover a broken car window
How to get a power window manually
Mechanical problems always seem to occur at the worst possible time, and those related to the power window system are no exception. If you are in the middle of a trip and cannot return your window to the closed position, use the following procedure to correct the situation:
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- Remove the door panel. Start by removing the interior door panel of your vehicle.
- Disable the window engine: Disconnect the power source from your window motor and store the matching pug safely.
- Disconnect the window controller. You will now remove all the fasteners from the window regulator.
- Raise the window manually. Placing a palm on each side of the window, gently lift the panel to a vertical position.
- Lock the window in place: You will now place 1 or 2 wooden blocks in the inner compartment of the door, thereby snapping the window into place.
- Reinstall the door panel: Finally, reinstall your vehicle’s door panel making sure all fasteners are tight.