Where is the oil pressure gauge/sending unit located?

Hi,

I attached a pic below showing the location. The idea that your gauge goes to the max with the key on/engine off tells me there is little to no resistance in either the oil pressure switch or the gauge itself may have failed.

As far as the sending unit, when the engine isn't running and producing pressure, the unit should have the most resistance, preventing power to the gauge. Once it starts, the resistance in the sending unit lowers based on how much pressure is present. The less resistance from the sensor, the more power to the gauge moving it to a higher indication.

The gauge is where the power starts. Power is run through a wire wound coil mounted at the pivot point of the needle. How far the needle moves is based on the resistance of the return wire which is grounded through the sensor to the engine block.

What this all means is there is no resistance. So, the switch could be bad, power is prevented from reaching to sending unit due to an open circuit, or the gauge itself is bad.

When you disconnect the sending unit, see if there is a power supply to it.

Let me know what you find or if you have questions. I hope I made that clear enough and didn't cause more confusion,

Take care,

Joe

See pic below.