49 CFR 571.104 – Standard No. 104; Windshield wiping and washing systems
S1. Scope. This standard specifies requirements for windshield wiping and washing systems.
S2. Application. This standard applies to passenger cars, multipurpose passenger vehicles, trucks, and buses.
S3. Definitions. The term seating reference point is substituted for the terms manikin H point, manikin H point with seat in rearmost position and H point wherever any of these terms appear in any SAE Standard or SAE Recommended Practice referred to in this standard.
Daylight opening means the maximum unobstructed opening through the glazing surface, as defined in paragraph 2.3.12 of section E, “Ground Vehicle Practice,” of SAE Aerospace-Automotive Drawing Standards (1963) (incorporated by reference, see § 571.5).
Glazing surface reference line means the line resulting from the intersection of the glazing surface and a horizontal plane 635 millimeters above the seating reference point, as shown in Figure 1 of SAE Recommended Practice J903a (1966) (incorporated by reference, see § 571.5).
Overall width means the maximum overall body width dimension “W116”, as defined in section E, “Ground Vehicle Practice,” of SAE Aerospace-Automotive Drawing Standards (1963) (incorporated by reference, see § 571.5).
Plan view reference line means—
(a) For vehicles with bench-type seats, a line parallel to the vehicle longitudinal centerline outboard of the steering wheel centerline 0.15 times the difference between one-half of the shoulder room dimension and the steering wheel centerline-to-car-centerline dimension as shown in Figure 2 of SAE Recommended Practice J903a (1966) (incorporated by reference, see § 571.5); or
(b) For vehicles with individual-type seats, either—
(i) A line parallel to the vehicle longitudinal centerline which passes through the center of the driver’s designated seating position; or
(ii) A line parallel to the vehicle longitudinal centerline located so that the geometric center of the 95 percent eye range contour is positioned on the longitudinal centerline of the driver’s designated seating position.
Shoulder room dimension means the front shoulder room dimension “W3” as defined in section E, “Ground Vehicle Practice,” of SAE Aerospace-Automotive Drawing Standards (1963) (incorporated by reference, see § 571.5).
95 percent eye range contour means the 95th percentile tangential cutoff specified in SAE Recommended Practice J941 (1965) (incorporated by reference, see § 571.5).
S4. Requirements.
S4.1 Windshield wiping system. Each vehicle shall have a power-driven windshield wiping system that meets the requirements of S4.1.1.
S4.1.1 Frequency.
S4.1.1.1 Each windshield wiping system shall have at least two frequencies or speeds.
S4.1.1.2 One frequency or speed shall be at least 45 cycles per minute regardless of engine load and engine speed.
S4.1.1.3 Regardless of engine speed and engine load, the highest and one lower frequency or speed shall differ by at least 15 cycles per minute. Such lower frequency or speed shall be at least 20 cycles per minute regardless of engine speed and engine load.
S4.1.1.4 Compliance with subparagraphs S4.1.1.2 and S4.1.1.3 may be demonstrated by testing under the conditions specified in sections 4.1.1 and 4.1.2 of SAE Recommended Practice J903a (1966) (incorporated by reference, see § 571.5).
S4.1.2 Wiped area. When tested wet in accordance with SAE Recommended Practice J903a (1966) (incorporated by reference, see § 571.5), each passenger car windshield wiping system shall wipe the percentage of Areas A, B, and C of the windshield (established in accordance with S4.1.2.1) that (1) is specified in column 2 of the applicable table following subparagraph S4.1.2.1 and (2) is within the area bounded by a perimeter line on the glazing surface 25 millimeters from the edge of the daylight opening.
S4.1.2.1 Areas A, B, and C shall be established as shown in Figures 1 and 2 of SAE Recommended Practice J903a (1966) (incorporated by reference, see § 571.5) using the angles specified in Columns 3 through 6 of Table I, II, III, or IV, as applicable.
Table I—Passenger Cars of Less Than 1520 Millimeters in Overall Width
| Column 1—Area | Column 2—Minimum percent to be wiped | Angles in degrees | |||
|---|---|---|---|---|---|
| Column 3—Left | Column 4—Right | Column 5—Up | Column 6—Down | ||
| A | 80 | 16 | 49 | 7 | 5 |
| B | 94 | 13 | 46 | 4 | 3 |
| C | 99 | 7 | 15 | 3 | 1 |
Table II—Passenger Cars of 1520 or More But Less Than 1630 Millimeters in Overall Width
| Column 1—Area | Column 2—Minimum percent to be wiped | Angles in degrees | |||
|---|---|---|---|---|---|
| Column 3—Left | Column 4—Right | Column 5—Up | Column 6—Down | ||
| A | 80 | 17 | 51 | 8 | 5 |
| B | 94 | 13 | 49 | 4 | 3 |
| C | 99 | 7 | 15 | 3 | 1 |
Table III—Passenger Cars of 1630 or More But Less Than 1730 Millimeters in Overall Width
| Column 1—Area | Column 2—Minimum percent to be wiped | Angles in degrees | |||
|---|---|---|---|---|---|
| Column 3—Left | Column 4—Right | Column 5—Up | Column 6—Down | ||
| A | 80 | 17 | 53 | 9 | 5 |
| B | 94 | 14 | 51 | 5 | 3 |
| C | 99 | 8 | 15 | 4 | 1 |
Table IV—Passenger Cars of 1730 or More Millimeters in Overall Width
| Column 1—Area | Column 2—Minimum percent to be wiped | Angles in degrees | |||
|---|---|---|---|---|---|
| Column 3—Left | Column 4—Right | Column 5—Up | Column 6—Down | ||
| A | 80 | 18 | 56 | 10 | 5 |
| B | 94 | 14 | 53 | 5 | 3 |
| C | 99 | 10 | 15 | 5 | 1 |
S4.2 Windshield washing system.
S4.2.1 Each passenger car shall have a windshield washing system that meets the requirements of SAE Recommended Practice J942 (1965) (incorporated by reference, see § 571.5), except that the reference to “the effective wipe pattern defined in SAE J903, paragraph 3.1.2” in paragraph 3.1 of SAE Recommended Practice J942 (1965) shall be deleted and “the areas established in accordance with subparagraph S4.1.2.1 of Motor Vehicle Safety Standard No. 104” shall be inserted in lieu thereof.
S4.2.2 Each multipurpose passenger vehicle, truck, and bus shall have a windshield washing system that meets the requirements of SAE Recommended Practice J942 (1965) (incorporated by reference, see § 571.5), except that the reference to “the effective wipe pattern defined in SAE J903, paragraph 3.1.2” in paragraph 3.1 of SAE Recommended Practice J942 (1965) shall be deleted and “the pattern designed by the manufacturer for the windshield wiping system on the exterior surface of the windshield glazing” shall be inserted in lieu thereof.