Okay, on my newly installed GPS unit one of the last functions
unconnected is to the "car speed signal". It isn't particularly clear
what this is. Other than sounding a lot like the pulse signal used by
the cruise control system. A (optional) accessory to use instead of the
"car speed signal" is the Pioneer ND-PG1 speed pulse generator.

So, what are the thoughts out there? (and of the two leads that attach
to the back of the speedometer, which (if any) should I connect to (if
it matters)?