Not true! As long as the sending unit is in the same ohm range for the sweep of the gauge it will work like a champ... My last sending units I got for my auto meter gauges I got from Napa Sent from my iPhone using SoCal Jet Boats
I got new hardin marine guages, I have autometer water temp and oil pressure senders, now both my guages are not reading . So maybe they r not in the same ohm range?