Oil pressure drop at 80mph

[spend]

Quickest check is to pull the single spade (not the supressor) off the alt & the charge light should go out ~ the remaining light is your oil pressure light.

You can double check this by pulling the oil switch spade term off & it should put the light out - touch it to ground & the light will come on

You should always check that switch when you start the car - oil failure is very expensive ( alt failure is trivial - dial instrument failure is trivial ) IMHO it is the most important information on your dashboard.

For some of us the light is yellow/orange BTW.

Dave