3rd Gen Dodge RAM 1500 2500 3500 Intermittent or not working Air Con. How to fix your broken RAM AC

Since I purchased my used 3rd Gen RAM 3500, I've had on again/off again problems with my AC.
Initially it was simply that it didn't turn on. An air conditioner regas fixed that temporarily, however it wasn't a permanent fix.
Finding the system had two leaks and fixing these leaks with another regas was though to fix the problem, but that left me with an intermittent AC.
The intermittent AC persisted for months and finally I couldn't take it any more. This problem had to be fixed!
Here is how I have got my AC working again and have finally been able to enjoy regular, reliable air conditioning in my RAM through the 2021 Australian summer.