Edited: another fuel/temp gauge thread, but turns out the harness is melted together

hotrod swinger said
When I ground the oil sender connector the warning light comes on when I turn the key (I don’t have the stock sending unit yet, just an aftermarket sender).

Also, the resistance at the aftermarket sender with the car idling is around 110 and with the engine not running is 10. Can I use the aftermarket sender or should I replace it with a stock sender?

The resistance of the sender sounds like an oil pressure sender and not an oil lamp sender. If it is quite large, IE about 2" dia x 2" or more long it is an oil GAUGE sender and not a "lamp" sender. A lamp sender should be a dead short to ground with engine off, and open with engine operating. "It's a switch"