Angus242164;68250 wrote
At freeway speeds the fans windmill and generate power, so if you have your indicator LED wired to the same pole of a SPST relay as the fan motor, the LED will light as a result of that current flowing.
To avoid this, I used a DPST relay with the motor wired to one pole, and the light (I was using a bulb) to the other, this way they were electrically separated when the relay was open. Using a bulb, I could watch it begin to glow faintly at about 70km/h, and get pretty bright at freeway speeds!
I've never seen any of my electric fans come on above 40km/h, even in very high ambient temps.
Upper or lower hose sensing methods both work well, as long as the switches are suited to the location. The setup on my 760 uses a sensor in the head and an adjustable controller, and holds the gauge needle rock solid under all conditions, and doesn't cause the fan to run for very long or too frequently at idle.
Note that virtually all OEM applications use sensors in the head or thermostat housing.
you can hear the fans running, as opposed to moving under pressure. My led is run by the trigger for the pull fan. You can see it light some days and others not, take this morning drive to work for instance, it never come on at any part of the drive unless stationary at the lights.
As when I have my 1200mm high pressure fan running in the garage. (I use it for static tuning of the cars, bikes and removal of exhaust gasses from the garage) the fans will spin and led is inactive.
also if im not mistaken, the factory gauges use a "compensation" circuit/board to reduce how much the gauge actually moves.
my needle doesnt move until the car has already boiled, and your stuffed.
PaulG;68324 wroteGreat info in this thread. Is there much less noise with the e-fan? Lose that noticeable 240 fan humming
its tonnes quieter. especially in the warmer months when the fan is more often engaged.
i like the set up better. and well im restricted to only using this set up. as mentioned earlier due to my intercooler depth
