I had a bushing in my brake pedal worn on my 420,000 mile truck. It would allow the pedal to bounce and interrupt the brake switch. I kept replacing switches until I noticed it was a worn pedal isssue.
Mine fan definitely kicks on a whole lot less when running empty with the dual thermostat mod. The temperature guage doesn't fluctuate nearly as much as it did before either. Not offering an opinion, this is just my experience.