Originally posted by DemonSVT:
If you dont watch the gauge, would you watch a tiny red light sooner?
...Personally I'll just watch my gauges until I remedy the problem of the stock pump. 
That's the beauty of idiot light it catches your attention, assuming you look at speedo frequently. Audible would be better of course.
Time from normal to danger temp, without coolant circulation, relatively short at highway speeds about 2 minutes (or 2 miles at 60mph). Impeller failure and wp belt failure have same result.
Haven't had time to think this thru' but I'm thinking that simple way would be to have fan relay work light (possibily low coolant light). Might require diode(s) or relay, but would also have to consider that a/c turns on fans.
