I have a '94 Ranger 4.0L and read the oil pressure gauge is really an idiot light. A simple switch and resistor in series with the gauge.

It looks like I can replace the sending unit with a real one, and bypass (short) the 20 ohm resistor on the back of the instrument cluster.

I see there is another resistor in series with the voltmeter.

Is that also just an 'idiot light' gauge similar to the oil gauge?

If so, how can I make it a real gauge?

Thanks, Mark.

 

Welcome to the forum

Volt meter is a Real gauge, although not very easy to get exact voltage from, digital displays are better.

Yes, oil pressure gauge used a switch, with 5.5psi as ON, under that is OFF.

You can install a PS60 sender on the engine and rewire the gauge, as shown here: Ford Oil Pressure Gauge Fix

Not sure I see that as needed since you either have oil pressure or you don't, lol.
But some like to see "real" oil pressure, just be aware that it will read VERY low at idle after warm up which is totally normal and safe for the engine.
This is why Ford changed to a switch, people who don't understand oil pressure just see a low needle and think there is a problem.
10psi oil pressure per 1,000RPMs, so idle at 700RPMs should be 7psi
And you want to stay under 60psi or bearing damage can occur

Oil pressure is very much like Blood Pressure, too low is bad and too high is also bad

 

True enough on the pressure or not thing, but it is nice to keep track over time. It just seems so wrong to have a two position gauge.

 

Yes, definitely a users preference

Took me awhile to get used to the 2003 CTS that didn't have a temp gauge, yes NO TEMP GAUGE.
GM did add it back in later models but geeze, I watch temp gauge religiously, made me nervous not having it, lol