At 11:27 AM 9/8/2011, T-rev Reynolds wrote...

>Is this item below a relay?  What function does this little plastic
>box do?  I suspect now that my problem may be within this 20 year old
>unit but don't even know what it does!
>
>http://i1003.photobucket.com/albums/af155/onsight2003/P1010392.jpg
>
>http://i1003.photobucket.com/albums/af155/onsight2003/P1010391.jpg

I'd guess it's either a brake/turn signal combiner (used to convert
European separate brake stop lights into a single signal for connection
to trailers), or it's to make the side marker blink with the turn
signal (legal requirement in some places).

If you can read Japanese, this might help:

http://yuccky.sakura.ne.jp/FCS-12.htm

the translation of this other page isn't particularly helpful:

http://translate.google.com/translate?sl=ja&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fyuccky.sakura.ne.jp%2FStanley%2520FCS-12.htm