One thing we wish we had in our motorhome was powered vents in the front and back. We often RV in an area of the country that doesn't always need the air conditioner running, so just a vent or two will keep the inside cool enough. As well, we sometimes boondock, so we don't want to have to run the genny to keep the air conditioner going.
Unfortunately the dealer did not order the front/rear powered vent option when the coach was built (although a powered bathroom vent is standard).
As it came to happen, one day while looking at the powered vent in the bathroom, I came to realize that it would not really be that hard to modify the other vents to powered vents.
When comparing the fan-powered vents to the manual vents, I discovered that there is not only a knock-out for the switch, but the center bracket was even pre-drilled for the fan motor bracket.
So I decided to see if the manufacturer "Ventline" had an upgrade kit for my vents (V2092). After contacting them, they indicated they did not have any such upgrade, so I would have to buy new vents.
Still, I was not going to give up on this, as I figured I could re-purpose a powered vent and transfer the motor and switch to the unpowered vents without having to remove the vents from the roof; which would make an easy project much more complex.
I was able to find over a dozen surplus stores on eBay selling new in-the-box V2094 vents (the version with the fan) for less than $40 (the MSRP for a new one is over $100). So I bought two vents, and was able to simply drill out the rivets in the motor bracket to retrieve the necessary components.
Installing the fan motor into the manual vents was easy with a couple of pop-rivets. I ended up using the new vent's switch plate as well as the old one had yellowed. It took all of about a minute to add the fan and switch to the existing vents.
The only real issue I was concerned about was wiring. How difficult is it going to be to wire up the fans?
As luck would have it, my coach already had wiring close by. The coach does not have a switched line for the overhead lights, but rather, each individual light has it's own on/off switch. This means there is a source of constant power at the switches.
In fact, when looking at the electrical drawing for my coach, when the powered fan option is ordered (circuit #3 on the drawing), the vent is wired into the light circuit. This tells me that there is not only sufficient power nearby, but the wiring and fuse are sized to handle the load of the vent... Easy, peasy.
I simply tapped into the lighting circuit to power the vents at both the front and rear units.
Once you have disassembled the new vent, and drilled out the motor bracket, the actual installation was not hard at all. As shown by the graphic to the right:
At this point, reassemble everything in the reverse order of disassembly. You have the option of substituting the new screen base (the one with the switch) for the original one, or punching out the square knock-out for the switch in the old base. I used the new base as the old one had yellowed.
Of course, you need to wire the vent fan before replacing the trim ring. You can use the new trim ring if you wish, however, for my installatin, the old trim ring was thicker (since I have a 6" thick ceiling), and the new trim ring was not long enough. If you have a damaged trim ring, or it has yellowed, you can buy a new one from Ventline as a separate item.
I also had to unscrew the ceiling light to get to the wiring. Running the wiring from the vent to the lights was easy with my "Harbor Freight" nylon fish tape. I have used this tool so many times...
From there, it was simply splicing into the wiring, then screwing both the light and vent trim ring back into place.
It should go without saying that DC power should be off whilst doing the electrical work.