One can easily source a "reed-valve" on ebay that senses coolant flow through heater hose,etc... Many of us have electric pumps. Very few have installed warning lights,or felt the need to. Modern electric pumps are super-reliable in my opinion. Temp gauge/light would certainly reflect a loss of function.
Winner 2001 Road Course (prep. class) Detroit,MI
Winner 2006 Drag race (SS class) Indianapolis,IN
Quickest event reaction time .013sec. (final-round)
Class Winner 2014 Charlotte,NC. 2016 NOLA car shows
Winner 2019 Road Course (prep.class) Pittsbugh,PA