I realize that this may be pretty obscure but just thought I would try and ask, basically, I have a Billion Variable Fan Controller (VFC) Pro. It is hooked up and currently works, I can adjust the fan temp as well as getting a correct temperature reading. The unit seems to be able to support an additional sensor though. When I was looking around for install instructions, I've seen posts where people say there is a way to attach an additional sensor, and then others correcting it and saying it is for the fan only, and I was curious to see if anyone knew for sure. It seems you can as I have another function on there for a sensor that currently reads 0, as well as wires that weren't used during the install. If I could connect an additional sensor how could I determine which types of sensors I could utilize?

EDIT: To clarify this is not the newer Billion VFC Pro DD, its the older grey one.

 

This one?

http://www.rx7club.com/showthread.php?t=510239

 

No, its this one but billion doesn't have it on their site.