Here's an image to a cooling system for your reference.
Each vehicle has it's own unique setup. The differences in some cases are slight and in some very big.
You can see the placement of your heater core.
Here's another image of a general layout for an AC system.
A Haynes service manual is about $20. They are worth their weight in gold if that's ...
D-GN Low Speed GMLAN Serial Data
2–3. Not Used
TN/BK High Speed GMLAN Serial Data (+) (1)
7–13. Not Used
TN High Speed GMLAN Serial Data (-) (1)
RD/WH Battery Positive Voltage
The points in green are those that are for use with extra equipment that you may want to fit dvd, cd changer, cameras front & rear etc etc
They provide these as if you drill holes in the metal body you affect the paint treatment and therefore the warranty protection - if the vehicle is out of the warranty then that is not so much of an issue...
So I was able to find a diagram of the 14 Fusion/MKZ and it's for the base system all the up through the SONY in the Titanium and the THX system available in the Lincoln. Here is the link for anyone who may want it in the future (and hopefully it doesn't die on anyone before they can use it!
2014 Fusion Audio Wiring Diagram