Interpretation ID: nht92-2.15

DATE: 11/20/92

FROM: O. SCHMIDT -- HELLA KG HUECK & CO.

TO: RICHARD L. VAN IDERSTINE -- VISIBILITY AND CONTROLS GROUP, NHTSA

TITLE: REPLACEABILITY OF LIGHT SOURCES OF CENTER HIGH MOUNTED STOP LAMPS (CHMSL)

ATTACHMT: ATTACHED TO LETTER DATED 12-11-92 FROM PAUL J. RICE TO O. SCHMIDT (A40; STD. 108)

TEXT: Since the introduction of CHMSL in 1985 it seems to be state-of-the-art in using non-replaceable light sources for CHMSL, so that in case of a failure the entire unit or the bulb carrier of devices with a number of light sources has to be replaced.

Could you please confirm that the wording of paragraph S 5.1.1.27 in subpara. (a)(5) and (b)(4) does not exclude the practice of using sealed lamps described in para. S 5.1.1.17, which is less expensive, especially in cases where long life light sources like long life bulbs, LED's and neon tubes are provided.

From our point of view the requirement in S 5.1.1.27(a)(5) and (b)(4) concerning the simple bulb replacement can be extended to the complete unit or bulb carrier, whatever the design of a CHMSL may be.

Many thanks for your interest.