[yetibone]

Is the oil pressure switch a Mopar part, or aftermarket? I've always had to get oil pressure switches for Chrysler vehicles from the dealer, because they're the only people that carry the correct type.

Every aftermarket oil pressure switch I found for a Chrysler was actually a variable resistance sender with two terminals, but the OEM sender is a single wire switch that grounds it's terminal to it's brass casing. The aftermarket sender will provide enough continuity to make the light flicker when there's drastic drop in pressure, like coming down to idle. The OEM switch doesn't have any continuity at all until ~3 psi.

If in the past some oil leaked out of a bad oil pressure switch and walked up into the casing of the wire, that can also contribute to the continuity necessary to light up the warning on the gauge cluster.