Are the white and red wires with the green and blue wires cut off, coming out of the brown casing for the thermostat?
And did you vent it through the ceiling or the wall?
Those pictures are exactly what I was looking for Thanks FastEddyG!!!!!!
Glad I can help. I had the gas and venting done for me as I am lucky to know what I don't know

They chiseled out the brick perfectly for the B-vent to go through the wall, which was a big concern for me.
That's correct, those wires are to my thermostat. It is vented horizontally through the wall, since over half of the area above the garage is living area, and the rest has no attic space. So horizontally venting was by far the easiest method. Luckily where it was vented was far enough back (from the front) that there wasn't a low soffit so we didn't have to have it stick out so far.
Here's a few more pics of my install (electric isn't hooked up in these pics) that I hope help.
-Ed
PS, the previous owner was the gem that tapped into the ceiling light fixture and ran wall mounted conduit to power 8 or so quad outlet boxes. I'll be fixing that when I get my subpanel in the garage.