Okay, I'm convinced. I will try your little weather windsock trick on my early model TJ, and go from there. I think it has the same issue. Your water valve reminds me of a story from my truck driving days. My first job as a truck driver was driving a new R model Mack in the upper plains states. I began in August, so it was still pretty warm. As the weather turned cold, I began to notice how perfectly ineffective the heater in that truck was. Scraping ice off the windows both inside and out while driving down the road in the falling snow convinced me that I needed to mention to my boss that I thought something might be amiss. He laughed and asked me if I had ever noticed that outdoor water faucet looking thingy under the hood. Yes, I had! He told me to turn it open until it stopped. I did, and things were so much better after that! Thanks for the video!

I watched to make sure I was installing on the proper hose but I need to point out that there's no reason to use a 3/4" ball valve, the inside diameter of a 1/2" is the same size as the ID of a 3/4 hose Barb and the price is less than half. Just go with a 1/2" ball valve with two 1/2 barb X 3/4 mnpt fittings and it's all good.

I’m curious, isn’t there an electronic valve from the factory that shuts off the hot water when you’re using the air conditioning?

I plan on doing this to my 2020 ram 1500. Can this cause any damage? Is it true that your coolant needs a constant circulation?