How do you test the oil pressure sender/switch

Good afternoon.

You would need a voltmeter to monitor the sensor or signal wire back to the dash unit.

I attached the description below.

Roy

This oil pressure indicating system incorporates an instrument voltage regulator, electrical oil pressure gauge and a sending unit which are connected in series. The sending unit consists of a diaphragm, contact and a variable resistor. As oil pressure increases or decreases, the diaphragm actuated the contact on the variable resistor, in turn controlling current flow through the gauge. When oil pressure is low, the resistance of the variable resistor is high, restricting current flow to the gauge, in turn indicating low oil pressure. As oil pressure increases, the resistance of the variable resistor is lowered, permitting an increased current flow to the gauge, resulting in an increased gauge reading.

I understand what it does, just wondering what to set the volt meter to? Ohms or volts? And what reading does it need to be? Does the car need to be running or can I do KOEO to key on accessory to monitor what the sensor is doing? And trying to understand the characteristics, if oil pressure increases, does that means the sensor is is monitoring and working?

You need to monitor the signal wire at the sensor with the engine running. The voltage will be low without the engine running and that reading will be low. When the voltage raises it sends a signal to the dash the gauge will rise.

They do not give voltage vs gauge reading specs.

You will have a 5 volt reference voltage, a ground and a signal return wire on the connector. The voltage on the signal wire will vary between 0 and 5 volts.

Roy

Okay, I will let you know what I find, but if the sensor is not in that range, does that mean there is a problem and it needs to be replaced correct?

That is correct.

Roy

May I have a diagram to know which wires are which? So I know I get the correct reading.

I cannot find a diagram of the connector but it is the tan wire that is the signal wire.

back probe the wire with the engine off and then with it running, there should be a change in voltage. 5 volts is sent to the sender unit.

Roy

You are right. I checked and voltage was changing, if it did not change it would not have pressure.

That is correct.

I would replace the sensor.

Roy

Is the sensor is working fine? I got 5 volts than readings were going all over the place. Does that mean it is bad if it does not stay steady at 5 volts? You mentioned there should be a change in voltage from 5 volts. It did change from 5 volts and sensor kept changing when engine was running.

It should go from 0 to 5 volts very smoothly. If it is all over the place, then the cluster gets confused on that voltage and does not know what to set for a reading.

Roy