R. Wender
P.O. Box 456
Flushing, NY 11365-0456

Dear Sir or Madam:

Your letter of April 26, 1996, to the Office of Vehicle Safety Compliance has been forwarded to this Office for reply. You have asked whether there are any Federal regulations that apply to an aftermarket accessory center highmounted stop lamp (we refer to it as a "CHMSL") that you have bought for use on a used station wagon that you bought. As you describe it, the CHMSL is ten inches long, one inch wide, and one inch deep. Mounted inside the rear window, the CHMSL contains four bulbs. When the brake pedal is depressed, each of the four bulbs is lit sequentially, from right to left then back to right.

Each passenger car manufactured on and after September 1, 1985, must be equipped with a CHMSL that conforms to Federal Motor Vehicle Safety Standard No. 108. Further, any aftermarket CHMSL that is intended to replace the original CHMSL must also meet the requirements of the standard. One of the requirements is that the CHMSL be steady burning when the brake pedal is applied, that is to say, that all light sources must illuminate simultaneously when the brake pedal is applied, and be extinguished simultaneously when the brake pedal is released. The purpose of this is to ensure that the CHMSL is instantly recognized as part of the stop lamp system, so that the driver following can apply the brakes without hesitation or take evasive action if needed. In the aftermarket CHMSL you describe, the four light sources are not illuminated or extinguished simultaneously, and for this reason the lamp could not be used as a replacement CHMSL on cars manufactured on or after September 1, 1985.

Apparently your station wagon was manufactured before September 1, 1985, since its manufacturer did not provide it with a CHMSL. In this situation, the accessory lamp is not replacement equipment covered by Standard No. 108 since it is not replacing an item of required equipment with which the car was originally equipped. However, we administer a law that forbids manufacturers, dealers, distributors, or motor vehicle repair businesses from making modifications that "make inoperative" any original safety equipment on the vehicle installed in accordance with a Federal safety standard. Because of the potential of a flashing CHMSL to cause confusion with the pair of steady-burning stop lamps mounted lower on each side of the vehicle, it is our opinion that the installation of the aftermarket CHMSL would make the regular stop lamps partially inoperative within the meaning of the prohibition.

The prohibition does not apply if the modifications to a vehicle are done by its owner, and you would not be in violation of the Federal statute if you personally installed the CHMSL. However, whether it is legal to use it depends upon the law of the state where the CHMSL is operated. We are not able to advise you about the applicability of New York law to the light and suggest that you contact the state Department of Motor Vehicles for an answer.

If you have any questions, you may refer them to Taylor Vinson of this Office (202-366-5263).


Samuel J. Dubbin Chief Counsel

ref:108 d:6/6/96