Causes of Power Window Failure and Fixed
When the window is open, drivers get anxious, worried about the possibility of rain or unpleasant cold. It’s a common nuisance that affects many people at some point. The mechanism that allows the up and down movement can fail in a variety of ways, causing it to only work in one direction.
Let’s take a look at the most common reasons why a window won’t go up and how to fix it, as well as how to open a window manually, all the way to the fix.
What causes power window failure and how to fix it
Below we’ll discuss some of the most common power window failures and what to do in each case.
1) No Circuit Current
A window regulator must have sufficient power to operate. This power comes from the vehicle battery and is most often routed through a fuse or a circuit breaker and relay.
If power to this circuit is interrupted, none of the switches will be able to open or close the window. The window switch must receive power first before it can pass power to the waiting window motor.
How to Fix the Problem
A reliable test light should be used to troubleshoot a power outage problem in the window circuit. With the door panel removed, check to see if your vehicle has power going to the input side of the power window switch. If the test light doesn’t come on, find the fuse this power is passing through.
In some cases, all of the windows may receive power from a single circuit. However, most vehicles split this power distribution onto multiple circuits. Often, the driver’s and passenger’s side windows on a vehicle are fixed separately from the rear windows. Often times, you will find that you have a blown fuse or a tripped circuit breaker. This is often caused by an aging window motor that draws too much current during operation.
2) Faulty Power Window Switch
Another common power window circuit fault involves the system’s power window switch. Over time, the internal switch contacts begin to deteriorate and are no longer able to establish continuity if the switch is tampered with.
Switch failure is the cause of a significant number of failures in power window systems. However, replacement is not recommended until such a condition is proven.
How to Fix the Problem
When attempting to diagnose a faulty window switch, the switch assembly must be removed from the appropriate door panel. A test lamp or multimeter is also required for diagnosis.
First, check to see if there is power to the window switch. If the connection is properly grounded, a test light will come on when power is detected. Alternatively, a multimeter should be used to check for 12 volts or greater on the power voltage wires of the circuit.
If input power is detected, repeat the process while holding the switch down to check for power to the outlet switch. If there is no power coming from the window switch outlet, replacement is required. However, if power is confirmed to be coming from the outlet, further testing is required at the system’s connection point to the window motor.
3) Faulty Window Motor
In some cases, a window lift motor may fail, but this is usually a by-product of deterioration of the internal circuitry. When this happens, your window won’t be able to move in any direction, which can be very frustrating.
A slow or noisy window motor is often a reliable indicator of the overall condition of the unit. If your window motor is properly grounded and receiving full voltage, but is still running at a snail’s pace, you should be suspicious.
How to Fix It: Fortunately, diagnosing a faulty window regulator motor is relatively easy. To do this, first remove the door interior panel. Next, find the electrical connection wire that corresponds to the faulty window lift motor. Disconnect the associated connector and check the harness side of this connection for power and ground while holding down the power window switch.
If there is power and ground, the window motor is faulty and needs to be replaced. The difficulty of this job varies depending on the vehicle model.
4) Broken Window Regulator
Like the window regulator motor, the window regulator unit can also fail over time. Over time, the mechanical components of a window regulator will fatigue, often leading to irreparable damage. In either case, a defective window regulator is usually relatively easy to diagnose.
If your car window won’t go up, seems to be tilted to one side, or has fallen into its frame, a faulty window regulator is almost certainly the culprit.
How to Fix the Problem
Diagnosing a defective window regulator requires a visual inspection. Removing the interior door panel gives you a relatively clear view of this unit. Thoroughly inspect the power window pivot, bracket, cable, and window clamp for signs of damage or fatigue. If any abnormalities are found, replacement is recommended.
Replacing a window regulator varies in difficulty depending on the model of vehicle being repaired. The process can range from simple and straightforward to extremely laborious. When in doubt, always seek the opinion of a professional.
