Interpretation ID: 2640o

Mr. Toshio Maeda
Executive Vice President
& Chief Operating Officer
Nissan Research & Development, Inc.
P.O. Box 8650
Ann Arbor, Michigan 48104

Dear Mr. Maeda:

This is in reply to your letter of June 30, 1987, asking for an interpretation of paragraph S4.1.1.36(b)(3) of Motor Vehicle Safety Standard No. l08.

That paragraph specifies in pertinent part that a replaceable bulb headlamp shall be designed to conform to Section 6.1-Aiming Adjustment Test, of SAE Standard J580 AUG79 Sealed Beam Headlamp Assembly. Section 6.1.1 states that "when the headlamp assembly is tested in the laboratory, a minimum aiming adjustment of +/-4 deg. shall be provided in both the vertical and horizontal planes." You have asked whether the aiming adjustment is to be achieved by the headlamp assembly, or by both the headlamp assembly "and by the headlamp when it is mounted on the vehicle."

SAE J580 applies to the design of headlamp assemblies, including the functional parts other than the headlamps, such as aiming and mounting mechanisms and hardware. The assembly may include one or more headlamps. Although the headlamp assembly is tested in the laboratory, its design must be identical to the headlamp assembly used on the vehicle. Thus, if the aiming adjustment requirement is met by the headlamp assembly in the laboratory, it should also be met when the assembly is installed on the vehicle. An individual headlamp installed on the vehicle need not meet the aiming adjustment test unless that headlamp is part of a headlamp assembly comprising only one headlamp.

I hope that this answers your question.

Sincerely,

Erika Z. Jones Chief Counsel ref:l08 d:1/14/88