Oil light not working

Mopar92 said
No. Every adapter I’ve ever owned was drilled and tapped. Seemed logical at the time. I didn’t T because I didn’t have one when I plumbed it.

I see. Many including myself have used the “T” in the factory location. Makes life easy. Wiring is smooth and hidden with the main harness. Picked my “T” up at Home Depot for $2.49. Took about 10 minutes total.
In the other case, if your adapter is insulated by gaskets it will not work. The pressure switch needs to be grounded to complete the circuit for the light.