FMVSS 118: Power-Operated Window, Partition, and Roof Panel Systems explained.

What FMVSS 118 says it is for

The eCFR heads this section "Standard No. 118; Power-operated window, partition, and roof panel systems." Under 49 CFR part 571, the Federal Motor Vehicle Safety Standards are the numbered standards that set safety performance requirements for motor vehicles and equipment. The text below is quoted from 571.118 as current through October 29, 2026.

This standard specifies requirements for power operated window, partition, and roof panel systems to minimize the likelihood of death or injury from their accidental operation.

What it applies to

The application section of the standard says:

This standard applies to passenger cars, multipurpose passenger vehicles, and trucks with a gross vehicle weight rating of 4,536 kilograms or less. This standard's inadvertent actuation performance requirements of S6(a) need not be met for vehicles manufactured before October 1, 2008. The standard's pull-to-close switch operability requirements of S6(c) need not be met for vehicles manufactured before October 1, 2010.

Applicability is decided by the text of the standard as written, including any exclusions it lists, and by the date-specific rules in it. This page does not decide whether a particular vehicle or item is covered.

How the standard is organized

The eCFR text of 571.118 has these top-level sections:

• S1: Purpose and scope
• S2: Application
• S3: Definitions
• S4: Operating requirements
• S5: Automatic reversal systems
• S6: Actuation Devices
• S7: Test procedures
• S8: Test rods
• S9: Procedure for measuring infrared reflectance of test rod surface material

In all, the text has 14 numbered headings. Use the finder above to search them; for example, a search for "test" lists the headings that mention tests.

Second-level headings at a glance

These are the numbered sub-sections one level below the top, in order (first 5 of 5):

• S7.1 Test procedure for testing power-operated window, partition, or roof panel systems designed to detect obstructions by physical contact or by light beam interruption:
• S7.2 Test procedure for testing power-operated window, partition, or roof panel systems designed to detect the proximity of obstructions using infrared reflectance:
• S8.1 Rods for testing systems designed to detect obstructions by physical contact:
• S8.2 Rods for testing systems designed to detect obstructions by light beam interruption:
• S8.3 Rods for testing systems designed to detect the proximity of obstructions using infrared reflection:

Key requirements, quoted from the text

These are excerpts from the requirements sections of 571.118, in the order the standard presents them. Long paragraphs are shortened where marked with [...]; the eCFR has the complete text, tables and figures, which this page omits.

S4 Operating requirements. Except as provided in S5, power operated window, partition, or roof panel systems may be closed only in the following circumstances: (a) When the key that controls activation of the vehicle's engine is in the “ON”, “START”, or “ACCESSORY” position; (b) By muscular force unassisted by vehicle supplied power; (c) Upon continuous activation by a locking system on the exterior of the vehicle; (d) Upon continuous activation of a remote actuation device, provided that the remote actuation device shall be incapable of closing the power window, partition or roof panel from a distance of more than 6 meters from the vehicle; (e) During the interval between the time the locking device which controls the activation of the vehicle's engine is turned off and the opening of either of a two-door vehicle's doors or, in the case of a vehicle with more than two doors, the opening of either of its front doors; [...]

S5 Automatic reversal systems. A power-operated window, partition, or roof panel system that is capable of closing or of being closed under any circumstances other than those specified in S4 shall meet the requirements of S5.1, S5.2, and, if applicable, S5.3. S5.1. While closing, the power-operated window, partition, or roof panel shall stop and reverse direction either before contacting a test rod with properties described in S8.2 or S8.3, or before exerting a squeezing force of 100 newtons (N) or more on a semi-rigid cylindrical test rod with the properties described in S8.1, when such test rod is placed through the window, partition, or roof panel opening at any location in the manner described in the applicable test under S7. S5.2. Upon reversal, the power-operated window, partition, or roof panel system must open to one of the following positions, at the manufacturer's option: (a) A position that is at least as open as the position at the time closing was initiated; (b) A position that is not less than 125 millimeters (mm) more open than the position at the time the window reversed direction; [...]

S6 Actuation Devices. Except as provided in paragraph S6(b), actuation devices in the occupant compartments of vehicles used to close power-operated windows, partitions, and roof panels must meet the following requirements: (a) An actuation device must not cause a window, partition, or roof panel to begin to close from any open position when tested as follows: (1) Using a stainless steel sphere having a surface finish between 8 and 4 micro inches and a radius of 20 mm ±0.2 mm, place the surface of the sphere against any portion of the actuation device. (2) Apply a force not to exceed 135 Newtons (30 pounds) through the geometric center of the sphere. This force may be applied at any angle with respect to the actuation device. (3) For actuation devices that cannot be contacted by the sphere specified in S6(a)(1) prior to the application of force, apply a force up to the level specified in S6(a)(2) at any angle in an attempt to make contact with the actuation device. The sphere is directionally applied in such a manner that, if unimpeded, it would make contact with the actuation device. [...]

S7.1 Test procedure for testing power-operated window, partition, or roof panel systems designed to detect obstructions by physical contact or by light beam interruption:. Place the test rod of the type specified in S8.1 or S8.2, as appropriate, through the window, partition, or roof panel opening from the inside of the vehicle such that the cylindrical surface of the rod contacts any part of the structure with which the window, partition, or roof panel mates. Typical placements of test rods are illustrated in Figure 1. Attempt to close the power window, partition, or roof panel by operating the actuation device provided in the vehicle for that purpose.

S7.2 Test procedure for testing power-operated window, partition, or roof panel systems designed to detect the proximity of obstructions using infrared reflectance:. (a) Place the vehicle under incandescent lighting that projects 64,500 lux (6,000 foot candles) onto the infrared sensor. The light is projected onto the infrared sensor by aiming the optical axis of a light source outside the vehicle as perpendicular as possible to the lens of the infrared sensor. The intensity of light is measured perpendicular to the plane of the lens of the infrared sensor, as close as possible to the center of the lens of the infrared sensor. (b) Place a test rod of the type specified in S8.3 in the window, partition, or roof panel opening, with the window, partition, or roof panel in any position. While keeping the rod stationary, attempt to close the window, partition, or roof panel by operating the actuation device provided in the vehicle for that purpose. [...]

S8.1 Rods for testing systems designed to detect obstructions by physical contact:. (a) Each test rod is of cylindrical shape with any diameter in the range from 4 mm to 200 mm and is of sufficient length that it can be hand-held during the test specified in S7 with only the test rod making any contact with any part of the window, partition, or roof panel or mating surfaces of the window, partition, or roof panel. (b) Each test rod has a force-deflection ratio of not less than 65 N/mm for rods 25 mm or smaller in diameter, and not less than 20 N/mm for rods larger than 25 mm in diameter.

S8.2 Rods for testing systems designed to detect obstructions by light beam interruption:. Each test rod has the shape and dimensions specified in S8.1 and is, in addition, opaque to infrared, visible, and ultraviolet light.

S8.3 Rods for testing systems designed to detect the proximity of obstructions using infrared reflection:. (a) Each rod is constructed so that its surface has an infrared reflectance of not more than 1.0 percent when measured by the apparatus in Figure 2, in accordance with the procedure in S9. (b) Each rod has the shape and dimensions specified in Figure 3.

S9 Procedure for measuring infrared reflectance of test rod surface material. (a) The infrared reflectance of the rod surface material is measured using a flat sample and an infrared light source and sensor operating at a wavelength of 950 ±100 nm. (b) The intensity of incident infrared light is determined using a reference mirror of nominally 100 percent reflectance mounted in place of the sample in the test apparatus in Figure 2. (c) Infrared reflectance measurements of each sample of test rod surface material and of the reference mirror are corrected to remove the contribution of infrared light reflected and scattered by the sample holder and other parts of the apparatus before computation of the infrared reflectance ratio.

Defined terms

The standard defines 1 terms in its definitions section; the first 1 are quoted here from the eCFR.

• Infrared reflectance means the ratio of the intensity of infrared light reflected and scattered by a flat sample of the test rod material to the intensity of infrared light reflected and scattered by a mirror that reflects 99.99 percent of the infrared radiation incident on its surface as measured by the apparatus show in Figure 2.

Limits of this page

This page quotes the text of 49 CFR 571.118 as published in the eCFR, current through October 29, 2026. It omits tables, figures, cross-referenced test procedures in other parts, and the preambles and rulemaking history that explain the rule. It does not tell you whether a given vehicle, part or product complies, how to run a test, or what a manufacturer must certify. Compliance questions go to the manufacturer's engineers, qualified counsel or NHTSA. The eCFR is an editorial compilation, not the official legal edition of the Federal Register.

Sources

Sources opened and read November 2, 2026.

• eCFR: 49 CFR 571.118, Standard No. 118; Power-operated window, partition, and roof panel systems. (current through October 29, 2026) (read November 2, 2026)
• eCFR: 49 CFR part 571, Federal Motor Vehicle Safety Standards (current through October 29, 2026) (read November 2, 2026)