windows are great as long as they roll up and down when commanded to do
so. But sometimes a window may quit working for one reason or another.
the fault is electrical, such as a bad power window switch, a blown
fuse, a bad relay or a loose or damaged wire. Other times, the fault is
a bad window motor or a broken part in the window regulator mechanism
that actually raises and lowers the glass.
The window lift
components inside the door usually include a small electric motor and a
window regulator assembly. The motor and regulator can usually be
replaced separately, though both require removing the inner door panel
to replace the parts. Replacement typically takes an hour or so, but
may require an extra set of hands to hold the glass while parts are
aligned and maneuvered into place.
The electric motors that drive
power windows are compact and powerful, and are similar to the motors
used on power seats. OEM motors can cost from $100 up to $300 or more,
depending on the application (imports and luxury vehicles are typically
On some vehicles, such as late model MINI
Coopers, the window motor brushes can develop dead spots after four or
five years of service due to lowering and raising the windows every
time the door is opened. It makes for a tight seal, but all the extra
motion also shortens the life of the window motor. Ford is using a
similar setup in late model Mustangs.
The regulator assembly that
raises the window is mechanical, and is subject to wear over time
whether it is power driven with a motor or is manual with a crank. Some
regulators use a steel cable and worm-drive gears to lift the window,
while others use a notched plastic belt or plastic strip with teeth for
the same purpose. Steel cables seldom fail, but plastic belts and
strips often become brittle with age and exposure to heat, and may
crack and fail, especially during cold weather. On some applications,
the plastic belt or strip can be replaced separately without having to
replace the whole regulator mechanism.
The plastic bushings and
slides in the window lift mechanism may also be subject to wear,
causing the misalignment or sticking when the window goes up and down.
This can result in a poor glass seal with wind noise and/or water
The regulator assembly is usually bolted inside the door
frame and attaches to the bottom of the glass. Regulators can be
relatively simple and compact, or large and complex. OEM replacement
regulators (if available) may cost $150 up to $600 or more depending on
the vehicle. For applications that are more than 10 years old, OEM
parts may no longer be available. Fortunately, there are aftermarket
repair parts available for many applications.
Related items a
customer might need when replacing window lift components include new
weatherstripping for the door, or weatherstripping adhesive or sealer
to repair loose or leaky seals.