Yesterday I got the radiator plumbed in in my mustang, it was running fine took it for a quick run up the road, not far, around half a mile, got back and the water in the rad was boiling, needless to say stopped the engine quickly. The electric fan didn't come on, removed the fan and tested it, that works fine. Would there be a temp sensor from the engine to allow current to the fan? It seems there is intermittent continuity on the wires to the fan, but surely this would be the case until the fan is activated. Could it just be as simple as a tits up thermostat? Haven't checked it as I was more interested in why the fan didn't come on.
p.s. before you ask there isn't a switch for the fan