Reset the One-Touch Power Windows

If the express one-touch feature on your 300 has stopped — the driver’s window no longer runs all the way up or down on a single tap — the door module has simply lost its window position memory. That happens whenever the battery or a door module is disconnected. The glass still moves while you hold the switch, so nothing is broken; it just needs to relearn its travel, which takes about a minute per window. Do it with the doors closed so the glass can seat fully.

How you know it needs a relearn

The classic sign on a 300 is that a tap-and-release does nothing, but pressing and holding raises or lowers the glass normally. Auto-down often keeps working while auto-up is the part that quits, because the module drops the upper reference first. It usually shows up right after a battery change, a door-card or speaker job, or a mirror swap — anything that unplugs a front door. On this platform only the two front doors have express, so the rears are unaffected and are not part of this reset.

1. Turn the ignition to the Run position. The engine can be off.
2. Hold the driver’s window switch UP until the window stalls fully closed, keep holding for at least two seconds after it stops, then release.
3. Hold the same switch DOWN until the window stalls fully open, hold for at least two seconds after it stops, then release.
4. Hold the switch UP once more until the window is fully closed, hold for at least two seconds after it stalls, then release.
5. Repeat steps 2–4 using the front passenger window switch.
6. Test express up and down on both windows.

Why it happens

Each front door module remembers the exact motor position of the fully-closed and fully-open stops so it can run the glass automatically and reverse if it meets resistance. Cutting power erases those stored endpoints, and without them the module disables one-touch as a safety default rather than slam a window it can no longer position.

If express still won’t work

• Hold roughly two seconds past the stall at each end — letting go the instant the glass stops is the usual reason the relearn doesn’t take.
• Do the driver and front passenger doors separately; each has its own module and only learns the window you cycle.
• Run the whole sequence a second time if either window still ignores a single tap.
• If express still fails after two clean attempts, suspect a door-module fault or a tired regulator dragging the glass — neither of which a relearn can fix — and have that door checked.

It is a good habit to redo this on both front windows any time the battery has been disconnected on your 300.