Interpretation ID: aiam0985
Alfred Teves GmbH
Postfach 119 155
Frankfu- rt/M
Germany;
Dear Mr. Lange: Mr. Paul Utans asked us to provide you with an interpretation o paragraph S5.3.3 of Motor Vehicle Safety Standard No. 105a, *Hydraulic Brake Systems.* Mr. Utans asks for confirmation of his understanding; >>>'that the indicator lamp shall remain activated either without th application of any pedal force or with one application of a pedal force (with a range of 25 or 50 pounds, as the case may be) if a failure of the kind described in S5.3.1(a) to S5.3.1(c) exists in the service brake system.'; This interpretation is only partially correct. Paragraph S5.3.3 state in pertinent part:; '...each indicator lamp, once activated, shall remain activated as lon as the condition exists, whenever the ignition switch is in the on position. An indicator lamp activated when the ignition turned to the 'start' position shall be deactivated upon return of the switch to the 'on' ...position... unless a failure of the kind described in S5.3.1(a) to S5.3.1(c) exists in the service brake system.'<<<; Paragraph S5.3.1(a) allows a brake pressure failure to be initiall indicated either before or upon application of pedal force, but thereafter the light must remain activated while the ignition switch is in the 'on' position. However, if the failure is present when the vehicle is first started, the indicator lamp must immediately be activated before any application of pedal force, until the failure condition no longer exists.This interpretation is subject to modification by response to petitions for reconsideration of Standard No. 105a, scheduled for publication around May 1, 1973; Yours truly, Richard B. Dyson, Assistant Chief Counsel