Search Interpretations

Interpretation ID: 22258-4.drn



    David Robertson, Manager
    Environmental & Safety Engineering
    Mazda North American Operations
    1500 Enterprise Drive
    Allen Park, MI 48101-2053


    Dear Mr. Robertson:

    This responds to your request for an interpretation of the requirements for heating/air conditioning controls specified in Federal Motor Vehicle Safety Standard No. 101, Controls and Displays. In particular, you asked about the identification requirements that apply to two controls that can be rotated indefinitely to increase or decrease fan speed and temperature inside the vehicle.

    Based on your letter, and the presentation of Mr. Masao Fujisaki, Overseas Certification Group, Environmental and Safety Engineering Dept., Mazda Motor Corporation, at a February 7, 2001 meeting with the agency, we understand that the two controls are located on the lowest part of a three-part control panel. The panel consists of the following:

      (1) at the top, an integrated digital display,
      (2) in the middle, the audio system controls, and
      (3) at the bottom, the fan/temperature controls.

    The digital display provides information about the audio and fan/temperature systems. Among other things, it shows fan speed and temperature. The digital display shows the fan speed by means of a right angle triangle labeled with the fan control symbol specified in Table 1 of Standard No. 101. The digital display shows temperature by means of a number followed by F, above which is the term "TEMP." We understand that the digital display is capable of providing "at least two levels of brightness."

    The fan/temperature controls consist of three round dial controls, placed in a horizontal row. The dial control on the right regulates temperature. The control is labeled at the top half by the ISO symbol for temperature (a thermometer). A plus sign (+) appears to the right of the temperature symbol and a minus sign (-) appears to the left of the temperature symbol. On the lower half of the right control appears the term "AUTO", under which "A/C" appears. The temperature control is turned on (or off) by pushing on the control. A warmer temperature is provided by turning the control to the right (clockwise); a cooler temperature is provided by turning to the left (counter-clockwise).

    The middle control consists of two adjoining, independent semi-circle pushbutton controls, which control the heating, cooling and defogging vents in the vehicle. The semi-circle at the top is labeled with the Table 1 symbol for the windshield defrosting and defogging system (by which air is directed towards the windshield), below which the word "Front" appears. The semi-circle at the bottom is labeled with the ISO symbol indicating upper and lower vents towards a passenger, above which the word "Mode" appears. One can tell whether a particular vent is actuated because the control stays pushed down when the vent is actuated. The windshield vent and passenger vents can either be operated independently or together.

    The control on the left is the fan control. It is labeled with the fan control symbol specified in Table 1 of Standard No. 101. To the right of the fan symbol is a plus sign and to the right of the fan symbol is a minus sign. Under the fan symbol is the word "OFF." The fan control is actuated by pushing on the control. To make the fan speed faster, the control is turned to the right (clockwise); to make the fan speed slower, the control is turned to the left (counterclockwise).

    On each of the three controls, all symbols (including plus and minus signs) and words are illuminated when the headlights are on.

    You are interested in how the S5.2.2 requirement that identification be provided for the "extreme positions" of controls that regulate a function over a quantitative range applies to the left and right controls. Because the controls rotate indefinitely, there are no extreme positions, in the traditional sense, that can be marked. However, the driver can know when the extreme positions have been reached by means of a digital display that shows the fan speed and temperature selected. You believe, based on your reading of an interpretation letter we issued on June 8, 2000, that use of a digital display is an acceptable means to identify the "extreme positions" of controls that regulate a function over a quantitative range.

    You noted, however, that the digital display in the design at issue is separated from the fan/temperature controls by the audio control portion of the panel. You asked whether this design meets the S5.2.1 requirement that identification of controls be "on or adjacent" to the control.

    The issues you have raised are addressed below.

    I note that S5.2.1(a) states in part:

      [a]ny hand-operated control listed in column 1 of Table 1 that has a symbol designated for it in column 3 of that table shall be identified by either the symbol designated in column 3 ... or the word or abbreviation shown in column 2 of that table. ... Any such control for which column 2 of Table 1 and/or column 3 of Table 1 specifies "Mfr. Option" shall be identified by the manufacturer's choice of a symbol, word or abbreviation, as indicated by that specification in column 2 and/or column 3. The identification shall be placed on or adjacent to the control. (Emphasis added.)

    Further, S5.2.2 states in part:

      Identification shall be provided for each function of any automatic vehicle speed system control and any heating and air conditioning system control, and for the extreme positions of any such control that regulates a function over a quantitative range. If this identification is not specified in Table 1 or Table 2, it shall be in word or symbol form unless color coding is used. If color coding is used to identify the extreme positions of a temperature control, the hot extreme shall be identified by the color red and the cold extreme by the color blue.

    In our June 8, 2000, interpretation letter addressing the use of digital displays to identify the extreme positions of controls that regulate a function over a quantitative range, we stated that it was our opinion that the requirement to identify the extreme positions is met as long as there is a means by which the driver can know when the extreme positions have been reached. However, we did not conclude that the "means by which the driver can know when the extreme positions have been reached" (i.e., the relevant displays) must be on or adjacent to the controls. In fact, your letter is incorrect in assuming, with respect to the system that was the subject of our earlier interpretation, that the relevant displays for both the fan and the temperature control system were located immediately below the digital display. While this is correct for the fan control (the fan was controlled by one of the push button switches), our letter states that the temperature controls (the outer rings around buttons labeled "PUSH A/C") were located away from the row of push button switches.

    Standard No. 101 does generally require that identification of controls be on or adjacent to the controls. Otherwise, there would be no logical connection between the identification and the control. This is why we made it clear, for the push button switches we addressed in our June 8, 2000, letter, that there needed to be close proximity between the switches and the images/identification.

    For traditional controls that regulate a function over a quantitative range, e.g., dials, levers or buttons that move only within a limited range, it makes obvious sense to require identification of the extreme positions to be located on or adjacent to the controls. This is the logical way for a driver to be able to identify the extreme positions.

    However, such a requirement does not necessarily make sense for new kinds of controls that regulate a function over a quantitative range, but do not have extreme positions in the traditional sense. For example, dials that can be rotated indefinitely are sometimes associated with a visual display. In a sense, the control consists of both the dial and the display. While it is obviously important that identification of the dial itself be located on or adjacent to the dial, there is no extreme position (in the traditional sense) to identify. And, whether for the system we addressed in our June 8, 2000, letter or for your system, we see no reason to interpret the standard to require the "means by which the driver can know when the extreme positions have been reached" (i.e., the relevant displays) to be on or adjacent to such dials.

    We note, however, that if the relevant displays are separated from the dials, there must be sufficient independent identification for both the dial and the separate display that the driver can understand both items. Our review of your proposed design does not indicate any problem in this area. For example, the dial for the fan control is marked with the fan symbol to indicate function and (+) (-) signs to indicate how fan speed is increased and decreased, and the display for fan speed shows the fan symbol to identify function and a triangle to indicate relative speed.

    I hope this information is helpful. If you have any further questions, please feel free to contact Dorothy Nakama of my staff at (202) 366-2992.

    Sincerely,

    John Womack
    Acting Chief Counsel
    ref:101
    d.2/28/01