As the temp keeps dropping, I think a little heating of the diesel fuel may help, but I have no idea when the stock fuel filter heater comes on and off, or if it's working at all.

Can I bypass the temp switch that controls the heater? and how?
What I want to put in an on/off switch, so I can manually switch it on when it's cold enough for me, and leave it on whenever engine is running.

I can see two wires on top of my filter assembly, one goes to the fuel line leaves the filter, I guess it's vacuum operated "fuel filter light sensor", the other one seems connect to the heating plate of the filter. the wire have some kind of shield on it. So what should I do?

Norman