seems to me if the scaling on the guage were changed it might be useful for daily use. i'm guessing that as the oil heats up the resistance of the sensor to 12vdc decreases allowing more current to move the needle. i suppose max temp allows most of 12vdc to the guage, but normal temp doesn't reduce the resistance enough to cause a deflection.
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there oughta be a way to allow more volts to the guage without having to screw with the guage it self ...
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must be sombody here with a phd in electricals who is smart enough to come up with a solution which is comprehensable to those of us who are crebrally challanged...
t.i.a.
flaps