Interpretation ID: aiam3541
Nissan Motor Co.
Ltd.
Engineering Office of North America
Suite 707
1919 Pennsylvania Avenue
N.W.
P. O. Box 57105
Washington
D.C. 20037;
Dear Mr. Suzuki: This responds to your letter asking whether your new wiping syste design meets the frequency requirements of Safety Standard No. 104, *Windshield Wiping and Washing System*.; By way of background information, I would point out that the agenc does not give advance approvals of vehicles or equipment. The National Traffic and Motor Vehicle Safety Act places the responsibility on the manufacturer to determine whether its vehicles or equipment comply with applicable standards. The following interpretation only represents the agency's opinion based on the information provided in your letter.; The system described in your letter operates on two settings. One o the settings provides continuous operation at a speed of about 75 cycles per minute. The wipers operate at the same speed for the second setting, but there is intermittence between each cycle. Because of the intermittence, the wipers operate only about 45 cycles per minute. As explained below, it is our opinion that such a system meets the frequency requirements of Standard No. 104.; Section S4.1.1 reads as follows: >>>S4.1.1 *Frequency*. S4.1.1.1 Each windshield wiping system shall have at least tw frequencies or speeds.; S41.1.2 One frequency or speed shall be at least 45 cycles per minut regardless of engine load and engine speed.; S41.1.3 Regardless of engine speed and engine load, the highest and on 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 subparagraph S4.1.1.2 and S4.1.1.3 may b demonstrated by testing under the conditions specified in section 4.1.1 and 4.1.2 of SAE Recommended Practice J903a, May 1966.; The primary issue for this interpretation is whether the system meet the requirement in section S4.1.1.1 for 'at least two frequencies or speeds.' This issue arises because the wipers operate at the same speed for the two settings, using intermittence to achieve a different number of cycles per minute. It is our opinion that the system does meet this requirement, since the language of the standard speaks of frequencies *or* speeds. While the speed may be the same for the two settings, the frequencies are different.; The system satisfies the requirements in section S4.1.1.2 and S4.1.1. that one cycle or speed be at least 45 cycles per minute, that the highest and lowest frequency or speed differ by at least 15 cycles per minute, and that the lower cycle be at least 20 cycles per minute (assuming that the requirements are met regardless of engine load and engine speed).; While your wiping system design appears to meet the frequenc requirements of Standard No. 104, we do have a possible concern about its safety. On its lower setting, between the periods of intermittence, the speed of the wiper blades would still be at a rate of about 75 cycles per minute. It is possible that operation at such a fast speed might cause chattering of the wipers when used during light precipitation. If that happened, drivers might be less likely to use their wipers during light precipitation. We suggest that you consider that possibility before going forward with your design.; Sincerely, Frank Berndt, Chief Counsel