i'd take a stab and say the above is correct, you probly just need to get one off ur original motor, or the same part from another motor, or a new one to suit your original motor.
Gauges and senders have to match.
for eg. In the daily driver sss, put a new motor in it, not knowing that whatever jdm awesome car the engine came out of, had a dif gauge temp sender, now my gauage reads oddly, but due to the stupid position of the sensor, its not being swapped over