The way I see it, you don't turn anything off. In fact, you don't ever want to turn off the air temp sensing circuitry, as it will most likely result in the warning light coming on.pancake said:I thought of that after I posted, but didn't reply. How would you turn off the real sensor to turn on the resistors? Because wouldn't if you ran a wire from the sensor out to the resistor and have a switch in between, then wouldn't it turn on both, or would the resistor override?
You are only switching between different circuits. For example, at normal, the current flows from the computer, out to the sensor, and back. In the modified resistor circuit, you simply create a shunt that causes the current to flow from the computer, towards the sensor, but is instead shunted thru the resistor (bypassing the sensor), and back to the computer. So if you have a switch box that allows such switching, you only toggle back and forth between the circuits, nothing is ever turned off. The current will flow no matter what, the variable is just thru what does it flow? Either the normal sensor, or the resistor.
If I recall my electrical engineering correctly, if you ran a resistor in parallel with the sensor like how you mentioned, it wouldn't give much change if any depending on the given resistance of the air temp sensor itself. Electricity follows the path of least resistance. On a hot day, the sensor will have a lower resistance, allowing higher current to flow thru it and less to flow thru the resistor (essentially cancelling out the presence of the resistor). As it gets colder and the sensor's resistance increases, I believe the sensor will maintain dominance over the 100 Ohm resistor until the sensor itself creates a higher resistance than the resistor. At that point, the max resistance will be the lowest resistance of the two. Or so I think. It's been years since I had this material.
Sorry Mensa, had to make my attempt to drown in my glass. I used to really enjoy electrical engineering back in my electric R/C car racing days.