Section 637 - Orientation MarkingsAftermarket lamps and reflex reflectors shall be marked with the word "top" on both the exterior and interior of the housing to designate the proper mounting position, except as noted in the following subsections. The markings on the interior of the housing shall be die-stamped or molded and shall be located so as to be visible when the lens is removed.
(a) Rotated Devices. "Top" is not required on a device which meets the test requirements when it is rotated about its axis 90 and 180 deg.(b) Housing. "Top" is not required on the housing if the lens is indexed in the housing in only one position and the word "top" is die-stamped or molded on the lens so as to be visible when the device is installed. "Top" is not required on the exterior of the housing when the interior is so marked and the lens must be removed to install the lamp on a vehicle.(c) Sealed or Semisealed Optical Unit. "Top" is not required on the housing for any sealed or semisealed optical unit if the lens markings on the unit are right side up when the unit is in its design mounting position.(d) Interior and Exterior. "Top" is not required on the interior of the housing if the exterior "top" marking is visible when the device is installed, nor on the exterior of the housing if the interior "top" marking is visible through the lens when the device is installed.(e) Location. "Top" is not required at the top of the device if the word is inscribed elsewhere with an arrow pointing from "top" to the proper mounting position.Cal. Code Regs. Tit. 13, § 637
Note: Authority cited: Section 26103, Vehicle Code. Reference: Sections 24006, 24012, and 26103, Vehicle Code.