Interpretation ID: nht90-3.78

TYPE: Interpretation-NHTSA

DATE: August 31, 1990

FROM: Paul Jackson Rice -- Chief Counsel, NHTSA; Signature by Stephen P. Wood

TO: Samuel Kimmelman -- Engineering Product Manager, Ideal Division, EPICOR Industries, Inc.

TITLE: None

ATTACHMT: Attached to letter dated 8-2-90 from S. Kimmelman to P.J. Rice (OCC 5074)

TEXT:

This is in reply to your letter of August 2, 1990, with respect to Motor Vehicle Safety Standard No. 108.

It is your understanding that, when a vehicle is delivered to its purchaser with dealer-installed trailer hitch and associated wiring, it must conform to all applicable Federal motor vehicle safety standards. You interpret the standards as requiring thre e specific aspects of performance, and you ask whether we agree with those interpretations. These aspects are:

"1. The turn signal flasher must be certified as meeting the FMVSS-108 requirements of a variable load turn signal flasher, over a minimum load equal to that of the vehicle turn signal load and a maximum load equal to that of the vehicle plus the trailer ."

This is essentially correct. However, it is not the flasher that is certified but the vehicle in which the flasher is installed; Standard No. 108 does not require certification of original equipment lighting items, only replacement equipment items. Sta ndard No. 108's requirements for turn signal flashers are those of SAE Standard J590b, Automotive Turn Signal Flasher, October 1965, which are incorporated by reference. Under the Standard's Scope, the flashers "are intended to operate at the design loa d for the turn signal system as stated by the manufacturer." If a vehicle is designed for towing purposes, and its manufacturer offers an optional trailer hitch and associated wiring, then that manufacturer must equip the vehicle with a flasher capable of meeting a minimum load equal that of the vehicle turn signal load, and a maximum load equal to that of the vehicle plus the trailer. That will be a variable load turn signal flasher. The manufacturer of the vehicle is the person responsible for ensu ring that the flasher meets the vehicle's design load requirements, and that the vehicle is certified as conforming to Standard No. 108.

"2. The hazard warning signal flasher must be certified as meeting the requirements of FMVSS-108 over a load range of 2 lamps to the combined hazard warning loads of the vehicle plus the trailer."

This is also essentially correct, and our comments are similar. Standard No. 108's requirements for hazard warning signal flashers are those of SAE Recommended Practice J945 Vehicular Hazard Warning Signal Flasher, February 1966, which are incorporated by reference. The Practice's Scope specifies that the flashers "are required to operate from two signal lamps to the maximum design load. . . . as stated by the manufacturer. Thus, in

order for the vehicle manufacturer to certify compliance with Standard No. 108, it must equip the vehicle with a flasher that operates over a load range of two lamps to the total hazard warning system load of the vehicle plus the trailer.

"3. The requirement to provide turn signal outage is voided due to the trailer towing capability of the vehicle."

This is correct. Under section S5.5.6 of Standard No. 108, any vehicle equipped to tow trailers and which uses a variable-load turn signal flasher is exempted from the failure indication requirements of the SAE standards on turn signals.

I hope that this answers your questions.