On another forum someone told me that in certain years Ford trucks with gauges were not equipped with normal analog sending units, but the senders were only OFF or ON type units, making the readings fairly meaningless.

Anyone heard of this? My 86 has normal sensors.

 

allot of the oil senders were like that. and it was only the sender. if you switched to a variable pressure sender, the gauge would work like it is supposed to.

 

If you know someone with a later model truck, and the oil pressure gauge always goes to the center of the scale, then they have the "fake" type of gauge. You can replace the sending unit to make it work correctly, but you also have to take the instrument cluster out and bypass a resistor on the circuit board. This resistor is what makes it read in the center of the scale when the on-off sending unit is "on".

 

I have the "fake" oil pressure gauge on my '03 van, and was going to attempt this "fix" when I heard about it some time ago. When I looked up all of the wireing, I saw that the sending unit (on/off) signal went first to the PCM, then on to the gauge and to the instrument clusters microprocessor.
Since I was adding other aftermarket gauges anyways, I decided just to add an oil pres gauge, and leave this circuit alone.
Still, I wonder if or how this mod might affect the PCM or other instrument cluster functions.
Anyone know what/why/how the PCM uses this on/off signal?

 

What type of van do you have? I looked up an 03 E-series, and it shows the sending unit(switch) going directly to the gauge in the instrument cluster. They actually describe the operation as the switch closing causes the guage to go to the normal range, and open it reads zero.

It's funny that they patronize the buying public who want a guage, but then hook it up so it's like an idiot light and does not show a true reading.

 

Sound like fraud to me. Very disappointing to learn about this.