Oil Pressure 0 and Check Gauges Light

I recently just changed my Oil Pressure Sending Unit on my 2.5 98 Wrangler because I broke it some time ago while trying to troubleshoot why the pressure was dropping to 0 and triggering the Check Gauges Light. Now that I have a brand new aftermarket sending unit installed, the oil pressure gauge stays at 0 without moving and with the Check Gauges Light on. The connector white/yellow wire in the connector reads 5v, and the gauge appears to be working because I did the dash gauge test operation (press and hold the mileage button while turning the key on). Also, my ODB2 tester isn't getting a low oil error code(I dont know if the PCM throws one). Is there a way to test if my sending unit is working? I have heard of brand new electrical parts not working.:confused: