Posted by David Sherman on Thursday, August 03, 2006 at 7:33PM :
In Reply to: Mopar Norm posted by Dan H on Thursday, August 03, 2006 at 6:54PM :
Wire it so if EITHER the ignition switch is on OR the thermostat says "HOT", the fan will come on. That way, the fan will keep running after you shut off the engine like on modern cars, which is a good idea because that's when the temp and press go really high. Or, if you don't want it running except when needed, put your own dash-mounted manual override switch in parallel with the thermostat. A lot of old military electronic gear has various "Battle Short" switches on it that short out safety interlocks, overpressure/overtemperature switches, etc in case of emergency. For example, a genset might have a "Battle Short" switch to override the oil pressure switch, on the theory that if you're in the middle of a war, you might care more about keeping the lights on and the radar operating for another few hours than about any extra wear to the engine due to low oil pressure, which would otherwise have shut down the genset. Most also have an indicator light to show you that the override is active.