How is Oil pressure light triggered?

Does it close / ground when you have oil pressure, or is it normally closed and opens when you have pressure.

Can they stick?

Started my car and it was 35 deg in garage. don't remember if the light came on when I first turned the key. and it was off when I was warming the car up. as usual.

But when I restarted it the oil light remained off. Seems it should have turned on.

I Think I replaced that light with an LED but not positive. (GEN bulb IS regular bulb, not LED)

This is the first time its happened.

The circuit is completed when the key is on with low or no pressure and opens when there is more than 7 psi to break the circuit. LED can be slow to respond. Try is several times by turning the key to on position and it should light up.

@Olympic 914

Whew, Looks like it is a non-issue. after driving the car a bit and getting it up to temp, everything reverted to normal.

So it may have been holding pressure with the cold oil, Or as Bruce stated the LED may have been slow to respond.

In 2020 you always expect the worse.