I have searched the forum and find a few mentions of this "upgrade" and thought this might help someone. You might be asking why do I need this. I like to run one fan drawing air in and the other one pushing air out, when weather cooperates, windows can be closed. If you also have the outside covers it will work whether its raining or snowing... air circulation is amazing. Having the forward / reverse pre-set and using the thermostat they will can do this automatically when temperature rises to a certain point.
My fantastic fans on a 2013 IS 23FB have many features but do not reverse. ... they have the automatic lifting lid, a rain sensor, thermostat (cool to warm), on/off switch, speed control switch (0 to 3). This mod is for this type of Fantastic fan. But, the idea is the same for all.
To make it reversing is simple. You will need to buy a switch (link below), have on hand or buy enough wire to make 2 pieces about 16" long of 14 awg insulated stranded copper wire (nice if one was blue the other black), but color doesn't matter if you can keep it straight in your head. I will refer to them later as blue and black you will have to adapt to what you used if your's if different. You will also need four insulated 1/4" blade quick connectors (there are other sizes) - three female and one male of the proper AWG range (I used blue); a way to cut and strip the wire and a crimper for the insulated terminals. And a medium Phillips screwdriver, I think the tip is a #3.
Make up the 16" long wires like this: on the blue wire put a male on one end the female blade connector on the other. On the black wire put female blade connectors on both ends.
Next, lift the vent lid a minimum of half way up either manually or via the lift switch... then turn the power switch to off and turn speed control to 0.
Remove the screws holding the inside panel - the one with all the controls on it. No need to remove the outer square trim ring, but might help to remove the screen. If you've never done this, you will see a place in the screen ring that allows you to get a finger in there and then pull carefully all around till its off.
You will be removing the screws that hold the lift motor in place as well. Then carefully pull the panel down to gain access to the connections on the back side; in particular the on/off switch and speed control. You will wish you have three hands at some point.
Next, remove the old on/off switch from the panel... slip off the quick connectors first ... both were white on mine... one runs to the motor the other is the (-) ground from the trailer wiring; then pry with a small screwdriver on the switch ends while pulling the switch off the panel towards the front. The catches are on its narrow ends.
Next, pop in the new reversing switch into the same hole... it fits. Mine did. If not you might need to enlarge it.
On the speed control switch you will see a blue wire that goes to the fan motor, remove it from the controller. Plug the new blue wire you made up with the male connector and push it onto the fan's blue wire's female connector (I would tape this connection so it won't unplug).
Then plug the new black wire you made up to the pin on the speed control you just removed the blue fan wire from.
Route both wires towards the new switch.
Now, connect the white that you took off the on/off switch that runs to the trailer wiring and plug into the - ground pin of the new switch.
Next, plug the black wire that you made up to the + DC of the new switch.
Next, plug the other white that came off of the on/off switch that runs to the fan motor and plug it into either of the Motor pins of the new switch and lastly plug the blue wire into the other motor pin of the new switch.
At this point I would test to be sure it works (lid was already up, right?). With the thermostat turned all the way towards cool (blue) and the speed control on "1", flip the new (3 position) switch all the way towards either direction and the fan should run. Then flip the new switch to off until the fan ceases to spin (or nearly) then flip it all the way in the other direction and the fan should run in the other direction.
If it passes, put it back together. As you fit the panel back into the hole, be careful to tuck all the wires inside as you go. The rain sensor wires are the easiest to miss. If they hang out the will hit the fan and make a heck of a noise. Put the screws back with the lift motor lastly as you replace all screws.
Test again. You might want to label the positions (air in - air out) of your choice or not.
The reversing switch I used is the GAMA 129-PR-MTD. It is a heavy duty 30 amp switch. Over kill, I was going for the size and type. You can get it directly from GAMA for $9.95 plus shipping or from Amazon with shipping for $16.95. I had two fans so I ordered two each.
Wire I had on hand but you can buy from various stores but I would NOT use solid copper. Same with the 1/4" connectors and crimper - automotive, hardware stores should have them. I used blue which works for 12 - 16 awg stranded copper wire. I show a photo of blue female for reference below.
I am attaching the link to GAMA and a picture which I also captured from this product on their site.
https://www.gamainc.com/product/129-pr-mtd/
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Linear Mode
