[TR] does sparking indicate a short?

[Randall]

> I guess, it wouldn't be sparking unless 
> something is
> shorted... right?

Unfortunately, it's not quite that simple.  Connecting to the 'hot' side of
the brake light switch like that, you are supplying power back into the
entire ignition circuit, which if the points happen to be closed, would
include the ignition coil.  That could be causing your sparking.

Randall