Interpretation ID: aiam1212
Staff Engineer-Electrical & Safety
Diamond Reo Trucks
Inc.
1331 S. Washington
Lansing
MI 48920;
Dear Mr. Shepard: This is in reply to your letter of July 19, 1973, asking whether a rea 'light signalling' switch may be installed on your vehicles.; As I understand your letter, the switch and circuitry in questio provide automatic flashing of side markers, clearance, tail, and identification lamps. Wiring of this nature, whether installed by the incomplete, intermediate, or final stage manufacturer would violate S4.6(b) of Standard No. 108 (formerly S4.5.8(b)). You are correct in saying that a switch and circuit may be furnished by manufacturers of truck-tractors, and incomplete vehicles for flashing only the side markers, and 'that trailer manufacturers and subsequent vehicle manufacturers shall be responsible for the electrical circuitry to insure that marker lamps are independent from clearance, tail, and identification lamps.' Of course, wiring these lamps to the same on-off switch would not violate the standard provided there is no flasher in the circuit.; You also ask 'who assumes the responsibility for older trailers whic will not have marker lamps on an independent circuit.' The person completing the circuitry on a trailer is responsible for compliance to standards in effect when the trailer is completed.; Yours truly, Richard B. Dyson, Assistant Chief Counsel