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Lexus: Why is My Power Window Not Working?

Every now and then comes the need to reset a car's battery. Often this can cause other components in the electrical system to reset, one of which is the electric window.

By Piyush Kayastha - December 10, 2014

This article applies to the Lexus IS, ES, GS, and RX (2005-2013).

Many newer vehicles have extensive electronic component programming. A common feature is the "one-touch window," which allows windows to roll up or down with one touch of your finger. If you've recently disconnected the battery, this feature may have gotten reset. You can follow this guide to have your vehicle re-learn this component. On older model Lexus cars, fuses or the actual switch can be the culprit. Another culprit can be interior Armor-all shine or a similar product. Many Lexus owners like to shine up their interiors during a detail, but there is a possibility of the main switch contacts getting wet in the process.

Materials Needed

  • Screwdriver to pry switch
  • Multiplex window computer ($50)
  • Window motor(s) ($75-125)
  • 30A fuse ($5)
  • Ratchet set
  • Fuse puller

Step 1 - Open the windows halfway

This is the first step in having the switch re-learn the the one-touch system. Perform this step on all windows.

Figure 1. Open all windows half way.

If the window is unable to come down or doesn't function, skip to Step 2.

Step 2 - Fully close the windows

Fully close a window by holding the switch all the way up for one second. Do this for all windows.

Figure 2. Use these controls to operate the windows.

Pro Tip

The indicator on the switch changes from a flashing pattern to steady when initialization is complete.

If the window is unable to come down or doesn't function, skip to step 3.

Step 3 - Inspect power window fuse

There is a related 30A fuse that could be blown. It could be shorted if a modified electrical component was installed without disconnecting the negative battery terminal first.

Locate the 30A fuse under left-hand side of the dash. Inspect the fuse to see if it's blown; if it is, replace it.

Figure 3. 30A fuse.

If the window is unable to come down or doesn't function, skip to step 4.

Step 4 - Inspect switch wiring

It is possible that the wiring to, from, and between the switch is faulty or broken. This can occur if electrical components have been replaced or modified.

  • Use a screw driver or flat edge object to pry up on leading edge of switch.
  • Inspect for broken or damaged wires.
  • Replace switch wires if necessary.
Figure 4. Pry off the switch panel and inspect the wires.

If this step doesn't resolve your issue, skip to Step 5.

Step 5 - Inspect door computers

There are multiplex door computers in each door that could be shorted out if an electrical component has been installed or modified without first disconnecting the negative battery terminal. There might be wires connecting to the "motor" that may be damaged as well.

  • Repair or replace wires if faulty.
  • Replace MPX module (Figure 5) if no current is shown on your voltmeter.
  • If module shows current but the motor doesn't, replace the Window motor (Figure 6).
  • Figure 5. MPX module.
  • Figure 6. Window motor.

Pro Tip

The module has been known to go before the window motor. it is best to isolate the problem at the same time, since you are already working in this area.

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