Hi,


My '95 Explorer 4WD XLT 4.0L was leaking oil from the oil pressure switch. I have replaced it but now the "gauge" seems to be operating backwards. With the key in the Run position, the gauge reads center but drops to zero on starting the engine. Have I put the wrong kind of sensor in - i.e., w/light vs. w/gauge? I bought a w/light since that's what the parts lookup on all the sites I looked at said to use. I thought it was a bit odd.


Any advice greatly welcomed!


Thanks for such a great resource.


John.

 

The "gauge" in the instrument cluster behaves more like a switch. If the oil pressure is enough to activate the switch, the "gauge" reads Normal. If the switch is bad or the pressure is low, it shows no pressure.

I'm not sure if the Explorer is expecting a N.O. or a N.C. switch. It sounds like it's expecting the opposite of what you received. I would guess that it wants to see a N.O. since that would be more of a fail safe approach (show no oil pressure if the switch is not function or unplugged).

-Rod

 

Thank you, Rod,


I have just tested the old unit and it does read open which makes sense. For a gauge, current needs to flow to read normal pressure but for a light current needs to flow to indicate low pressure.


So now I'm puzzled as to what to get. Obviously I need one that says "for gauge" but I thought the technology was different (i.e., a switch is a metal diaphragm). Are NC switches available (i.e., fully open or closed)?


I think I have just learned that just because it says it fits doesn't mean it's right...

This is the 'for light' version I bought:


This is 'for gauge':


If the second one is what I need then I can get one from my local parts store and send the other back.


Thanks again,


John.

 

Yeah, it appears that, even though the gauge isn't really a gauge, the parts houses consider it as the "w/ gauge" version. From what I find, you want the .

-Rod