Oil pressure gauge reads 75lbs cold,,, 30lbs oil warning light on ,,, changed switch checked all the wires ,light still on oil gauge still 75lbs......what am i missing here

Is it a mechanical gauge or electric? Did it work ok before now? What changed? Is it a normally closed switch? I have a mechanical gauge (Autometer) that reads 80 lbs, sitting on the shelf.
Brian

Gauge is mechanical, works fine ...The light just come on ,so i changed the old pressure switch to a new one ,,,But the problem is still there it does not even flicker ...I will make up a gauge and put it in place of the switch to see if i have got pressure there but the bleed of for the gauge is only about half inch below switch ????