Originally Posted by overlander63
You can install a Maxx-Air vent cover over the other vent, and leave it open. It won't rain in unless you are in the middle of a hurricane. The maxx-Air fan you have now will pull or push the hot air out, leaving cooler air inside. We run our fan on "intake", which forces the hotter air out the open, but non-powered, vents.
This is basically what we did, we installed a two-way Fantastic Fan over our bed in the Safari with the Maxx Hood. This was we can leave it open all the time even when towing. When the AS will be parked in the drive for a while we will open one of the back windows, turn the fan on low out and the trailer stays cooler and fresh.