Interpretation ID: nht74-3.7

DATE: 12/11/74

FROM: GERHARD P. RIECHEL -- ATTORNEY VOLKSWAGEN OF AMERICA INC

TO: TAYLOR VINSON -- OFFICE OF THE CHEIF COUNSEL NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION

TITLE: STANDARD 105 - FAILURE INDICATOR LAMP

ATTACHMT: ATTACHED TO LETTER DATED 02/28/75 FROM RICHARD B. DYSON -- NHTSA TO GERHARD P. RIECHEL, RED BOOK (-); STANDARD 105-75

TEXT: Dear Mr. Vinson:

This is in reference to our meeting of Friday, November 22, and previous telephone conversations concerning the permissibility of Volkswagen's brake failure indicator configuration for use in connection with 1976 model vehicles.

We have understood Paragraph S5.3.3 of FMVSS 105-75 read in conjunction with S5.3.1(a)(1) to permit deactivation of the failure indicator lamp whenever the brake system is not under pressure, that is whenever brake activation terminates. Mr. Bloom informed us that this understanding did not accurately reflect the intent of the language of the Standard nor the purpose that its authors sought to achieve.

While we appreciate the difficulty of drafting regulations dealing with complex technical subjects, we believe that the language of the rule should be accorded priority where a contrary intent and purpose are not readily apparent. We have closely examined each notice issued by the NHTSA in the course of the lengthy rulemaking process relating to Standard 105 and find nothing that would have aided us in ascertaining the claimed intent of the rule.

It should also be noted that unlike certification, recall and record keeping regulations promulgated by the NHTSA, its safety standards are addressed to design engineers, who are accustomed to working with measurable and ascertainable values and conditions. A "gross loss of pressure," an engineer would justly maintain, simply cannot exist in the absence of any pressure in the brake system. One could argue that had the rule's authors intended the indicator lamp to remain activated as long as the brake system was so grossly defective that it was incapable of building up pressure, terms similar to "inability to build up pressure" or other such language would have been chosen. There is little doubt that our engineers chose that meaning, which most closley conforms to the letter of the standard, and totally unaware of the subsequently disclosed "intent" of the rule, acted responsibly in designing and developing a brake failure warning and indicator lamp configuration, which now is ready for production and use in connection with 1976 model cars.

Description of the Volkswagen Brake Failure Warning System and its Advantages Over Other Systems

Volkswagen uses a dual chamber master cylinder, which provides operating pressure to both brake circuits. The system is so designed that leaks in one circuit will not affect the performance of the other circuit. An electrical warning system, which is actuated by a pressure switch in each of the two brake circuits, which is located in the master cylinder, causes a red indicator lamp on the instrument panel to light up whenever a gross loss of pressure occurs in one of the two circuits upon application of the brake pedal with a control force of not more than fifty (50) pounds. The two pressure switches perform dual functions. Under normal operating conditions, they operate the tail brake lights. Both pressure switches are actuated simultaneously as the result of pressure built up in each circuit. In the case of a gross loss of pressure in one of the circuits, the pressure switch for the other circuit is actuated and in turn illuminates the tail brake lights and the warning indicator lamp upon application of the brake pedal. When the brake pedal is released, the warning and tail lights are deactuated.

This type of pressure failure warning system has certain advantages and, we believe, is superior to warning systems incorporating latching relay components, which allow the warning lamp to remain activated even if the brake pedal is released. Latching relay components have the disadvantage that they operate only in the event that a failure occurs. Unused, they may become increasingly unreliable as the vehicle ages. There is no way of checking, short of dis-assembly, whether or not they are operative. With the increasing age of the vehicle, possible malfunctions due to corrosion and other causes remain undetected until such time as the actual pressure loss occurs. Volkswagen's warning system offers a means of checking and assuring continuous operation throughout the life of the vehicle.

Additionally, since the Volkswagen pressure switch does not only sense a pressure loss but also any malfunction in the switch itself, which, if it occurs, would activate the indicator lamp, the driver is made aware of any deficiency in his braking system.

The Volkswagen warning system also enables the vehicle operator to distinguish between a pressure failure signaled by the warning light being deactivated upon release of the brake pedal, and a loss of brake fluid. In the latter instance, the warning light will remain activated independent of any brake pedal activation.

Notwithstanding the unpublished intent of the rule, which was unknown to us until recently, we believe there is ample support for our claim that the Volkswagen design falls squarely within the interpretive parameters of the Standard's language. We therefore believe that our design is permissible under the law without further rulemaking.

In the event that the NHTSA should disagree with this view, we respectfully request that the effectiveness date of Paragraph S5.3.3 to the extent that it makes reference to Paragraph S5.3.1(a)(1) be postponed until September 1, 1976.

Volkswagen is currently committed to produce the system described above and in more detail in Attachments 1, 2, and 3.

In order to meet the alleged intent of the rule, it will be necessary to redesign our current warning system in several respects. Attachment 4 shows the circuit diagram of the new system, and Attachment 3, the changes that are necessary in the lamp housing in order to accommodate the additional components. The changes are marked in red pencil.

Enclosed as Attachment 5 is an estimate of the cost that we anticipate in acquiring new tooling and in tool modifications for the purpose of incorporating latching relay components into the warning system of each of the models offered for sale in the United States. Note in particular the high costs that will be incurred for our two new models, the Rabbit and Scirocco. The single largest cost factor in this case involves major changes on the dashboard support structures on these models to receive the larger components of the new lamp assembly. The dashboard changes as well as the modifications of the instrument panel insert are marked in red pencil in the drawing enclosed as Attachment 6. The total cost for new tooling is estimated to be approximately $400,000. The cost to the manufacturer of the additional components that must be installed in 1977 vehicles is approximately $4 per car.

Redesign and preparation for production including development of the additional tooling is estimated to require approximately 20 months.

Your favorable consideration of our request is appreciated.

Sincerely,

ENCS