Interpretation ID: nht73-1.29

DATE: 08/13/73

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: Diamond Reo Trucks, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of July 19, 1973, asking whether a rear "light signalling" switch may be installed on your vehicles.

As I understand your letter, the switch and circuitry in question provide automatic flashing of side markers, clearance, tail, and identification lamps. Wiring of this nature, whether installed by the incomplete, intermediate, or final stage manufacturer would violate S4.6(b) of Standard No. 108 (formerly S4.5.8(b)). You are correct in saying that a switch and circuit may be furnished by manufacturers of truck-tractors, and incomplete vehicles for flashing only the side markers, and "that trailer manufacturers and subsequent vehicle manufacturers shall be responsible for the electrical circuitry to insure that marker lamps are independent from clearance, tail, and identification lamps." Of course, wiring these lamps to the same on-off switch would not violate the standard provided there is no flasher in the circuit.

You also ask "who assumes the responsibility for older trailers which will not have marker lamps on an independent circuit." The person completing the circuitry on a trailer is responsible for compliance to standards in effect when the trailer is completed.

Yours truly,

July 19, 1973

National Highway Traffic Safety Administration, Department of Transportation

ATTENTION: Office of the Administrator

SUBJECT: Request for interpretation of use of interrupting switch for flashing vehicle lighting for signalling purposes.

REF: Part 571.108, Standard 108, Paragraphs 54.5.3 & 54.5.8 (b)

Dear Sir:

As a manufacturer of heavy duty motor trucks, Diamond Reo Trucks, Inc. receives many customer requests for a "light signalling" switch, which we have refused to furnish.

Paragraph 54.5.8 (b) permits flashing of headlamps and side marker lamps. Is it the intent that a manufacturer of truck-tractors (complete vehicle when 5th wheel is installed) and original manufacturer of "Vehicles Built in Two or More Stages" may furnish a switch and circuit for flashing markers only, and that trailer manufacturers and subsequent vehicle manufacturers shall be responsible for the electrical circuitry to insure that marker lamps are independent from clearance, tail, and identification lamps? If so, who assumes the responsibility for older trailers which will not have marker lamps on an independent circuit?

Customers report that other truck manufacturers do furnish a rear lighting signalling switch and, due to our refusal (based on our interpretation) to offer this type of switch, Diamond Reo is being placed at a disadvantage when bidding on vehicle build contracts.

Your immediate interpretation will be appreciated.

Very truly yours,

DIAMOND REO TRUCKS, INC. -- R. D. Shepard, Staff Engineer - Electrical & Safety

cc: G. Sztykiel