This link shows standard #108 of Title 49, Part 571, motor vehicle safety standards, brought to you by the folks at the NHTSA/DOT. It would appear that the SAE's report of January and February, 1966, spell out the characteristics of a 'Hazard Warning Signal'. http://frwebgate.access.gpo.gov/cgi-bin/get-cfr.cgi?TITLE=49&PART=571&SECTIO N=108&YEAR=2001&TYPE=TEXT The newly created DOT enacted its first score of laws on January 31, 1967. Included in this would be a Hazard Warning Signal device. The chronology of the Dept. of Transportation can be found at, http://isweb.tasc.dot.gov/Historian/chronology.htm#1967 There are pre '67 cars with 4-way flasher units; the 1966 T-Bird Town Hardtop and Landau had them included in their "overhead safety panel" as featured by the Pilot in this link http://automotivemileposts.com/tbird1966standardequipment.html This link shows a picture of a flasher unit mounted under-dash on a '66 Pontiac GTO. The caption describes it such that it may be 1967 when GM officiated the switch to the steering column. http://ultimategto.com/scripts/showcar.cgi?type=show&pic=/1966/66_00066_4 Chrysler typically used the glove box for the placement of 4 way flashers in '67-8. So, the question is, were flashers an option up to the models produced before January 31, 1967, or did all '67 model year Chryslers get 4 way flashers as standard, required by govt edict, equipment? Eric '63 Crown Four-Door '72 Newport Custom Sedan ************************************************************** I have earlier cars with factory installed units also (my 65 Ford for example), but I was addressing the federal mandate - specifically when they were made mandatory on US production. To add to the confusion here, I presently own two 1966 Imperial LeBarons. ONE has flashers and one does not. The one that does has a separate switch mounted on the bottom left side of the dashboard to turn then on&off. I also previously owned another '66 LeBaron and it did Not have flashers installed either. I do not know the production dates of any of the three cars.