I put two of these behind the top fridge vent. I wired them in series to slow and quiet them down. We had been camping in the Southwest a lot a couple years ago and I was wanting to move more air. Work beyond my expectation, the fridge stayed cold in 100+ degree days.
https://www.ebay.com/itm/Universal-9-inch-12V-80W-Slim-Push-Pull-Electric-Radiator-Cooling-Engine-Fan-Kit/154127885081?_trkparms=ispr%3D1&hash=item23e2bce319:g:Gx4AAOSwv9pfQAWb&amdata=enc%3AAQAFAAACgBaobrjLl8XobRIiIML1V4Imu%252Fn%252BzU5L90Z278x5ickkxGz2ccqatkEnoeekHqhLkds0njexIh9xtwk9DIHqppb%252BNv4ItQibIoz35eKcrHB4r90%252BaU8BXiLJymrWMuvSE4%252FXhDHYEh4ApgrpfZJ4lRVE%252BuIbahyX0ZPb9zzj%252FtyczhSfRozpWYk4OieXAdW8DEVdEyZNxAaCeuroNwn78PSM%252BBOj9EEyPI9tx1UskFbXDoqyf0nxlfvERo8qhbP3WTDaB6KhMgjomG%252Br2r%252FJ6%252FnFh6Cm4kRslVXssSfrHOAR8g68p4ElL3qPvzfzeqZZ%252Byf6IMgh%252Bd6yqv6oOMULnkvZt9mFT41cuqN%252Fj4wR0m9q5gFcwbm0gJXo%252Be%252FYqgdxopiUmNNuyHwSTeXJrzdKmTkRPV9czK6eqwjLS8SqQMcbcTPr8UHHIfznsOqSq7Ssf3adiP%252BJsuqFp7SY8FSH8zpOcyu8IryXSm1%252BV9KKmMwlX46swsNHqHJpPiJY9ELpo8fqH766nWRz9D1XqBMzhvZktK7ZVgxrXc9oeZuP9xK11wE8JnUyu5KFDBetBNLuRGfhz3q9psJDtHnF1DECH2%252FFEPXWS9IA9WuXLntJJ1IVRwQPyU1eSHZGTg30RWXGfQlXjxePNqUhlqw7HLYNdHXOaWYUIwnjpMliGDT9jC9Bz95tlfBdpX0zKL%252Bud1kkaqS2tLBRIaI2RzvPnlvskppyNeTH4mb4l1lGTaxiGh4lu%252F%252FQUmaXemHEhbJxFVAOJpPUmqZhxX7b6vYQYUd4J7tvOZSSzr4P1oWPekCyNxo%252BJbK1fJwRKh1N%252B7apHe3J6tOUSRjws69rxgkKU43H3oE%253D%7Ccksum%3A154127885081709e9811a516408d88ff40318c41cad0%7Campid%3APL_CLK%7Cclp%3A2334524