The resistance range for my original two wire sender was 0-160 ohms and the resistance range for the three wire sender I replaced it with is 0-600 ohms. Either the two or three wire sender can be used (provided the gauge is analog) by just leaving the third wire (white wire) unconnected in the engine bay.
Original two wire sender was a 90 degree movement linear resistor approximately (measured by me), the three wire unit I replaced it with is approximately a 350 degree Pot (measured by me) and less than 1/4 turn of it is used (so it is roughly equal ohms per degree).
My drive full down is -6*, full up is +53*. Total movement is approx. 60*. My gauge (Faria) reads full down at 11 ohms and when full up reads above the “UP” dash mark (60* x 1.7 ohms/ degree + 11ohms = 111ohms. It should be noted that the gauge is not linear but exponential. The gauge is far more sensitive at lower ohm measurements.
This now leaves us with a quandary – Is the drive not moving through it's full range or is there a problem with the sender?
1/10 of a turn is 36*, 1/8 of a turn is 45* and normal (by my SX-M 2004) is 59*, which is it?
Three wire senders are just normal rotary potentiometers and cheap knock offs can be DOA (buy OEM) and add 3M 5200 around the wire inlet seal.
The original two wire sender was a linear wire wound resistor of superior construction but the wire entry let water and caused it to fail. I know that you have to pay more for a two wire sender but I don’t know if it is still a wire wound resistor or just a three wire with the travel restricted and a wire missing!
Set the sender to 11 ohms and see if the gauge reads full down, then set it to 110 ohms and see if the gauge reads full up, if it does the gauge is good.
Are you sure your drive is going all the way down?
All these readings / figures are from my drive not specifications use at your own risk!
