It's very unlikely that the vent is pre-wired for your needs. However, the good news is that almost all ceiling vents in TT's have power within 2 or 3 feet of them in the form of overhead lights of some kind. While some are controlled by a wall switch, many are not which means that there is both +12vdc and ground available.
If you remove the knob and the inside plastic shell from the vent you will be able to see the framing around the vent. If there is a light fixture nearby, all you will have to do is drill a single hole, maybe 1/2" or a bit less, and run your hot and ground wires from the vent opening over to the light. Drop the light and there should be a good sized hole in the ceiling where you can bring the wires out.
Use a couple of these connectors (readily available at any auto parts store) to piggy back onto the wiring of the light:
Use 14 awg wire, also from the auto parts store, and remember that RV wiring is kind of the reverse of the rest of the world. White is ground and black is hot.
This is a pretty easy job and should only take a few minutes to get the power over to the vent opening.
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'11 Cougar 326MKS loaded with mods
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