User:Mardus/Sequential turn signals

Sequential turn signals are a feature on some cars whereby the lights that form the rear turn signal don't follow the simple pattern of on then off, repeating, but instead perform a more complicated sequence. This is obviously much easier to do on an American car because of the common usage of the same red tail lights as both brake/tail lights and turn signals; there is therefore much more room for creativity than with the European and Japanese usage of separate yellow turn signals and red brake and tail lights.

The most common sequence employed requires three red lights per side that can be used as turn signals. The innermost light is lit first, followed by the middle light being lit, then the outermost. All are on for a brief moment, then all turn off and the cycle is repeated, giving a kind of strobing, directional effect.

Sequential turn signals were factory fitted to Ford Thunderbirds built between 1965 and 1971, inclusive, to Mercury Cougars between 1967 and 1973, to Shelby Mustangs between 1968 and 1970, and to 1969 Imperials (built by Chrysler). No other production cars were so equipped; this may have been due to worries about the system's complexity, as well as to changes in automotive fashion.

Two different systems were employed. The earlier, fitted to the 1965 through 1968 Ford-built cars, was electro-mechanical, featuring an electric motor driving, through reduction gearing, a set of three slow-turning cams. These cams would actuate switches to turn on the lights in sequence so long as the turn signal switch was set. This system was complicated and prone to failure, and therefore the units are non-functional in many surviving cars. The part is long out of stock at Ford and it is practically impossible to find a NOS unit. An electronic replacement unit is available from several suppliers.

Later cars used a transistorized 'black box' with no moving parts; this was much more reliable. The sequential unit can be found in the trunk on Cougars and Thunderbirds, affixed behind the back seat or on the driver's side of the trunk behind the lining in all model years that had them. The 1969 Imperial also used a transistorized unit.

Aftermarket sequential units are also available to install on other cars. Usually these require that the vehicle have three lights on either side which can be converted to such use, but conversion units for two or four lights do exist.

Sequential turn signals are legal in all states of the USA and Canadian provinces. Sequential brake lights (where the same circuit is used for when the brake lights come on, which has never been done on a production car) are illegal in several states, including New Jersey and Florida.