Need help finding new temperature gauge

Great news! I put the cluster back in the dash and both gauges work! Woot!

E-brake lamp works, but the oil pressure lamp does not. I assume it's supposed to light up as I'm starting the car? Can I ground the oil pressure sending wire in order to get the bulb to light up, or no? I tried it and still nothing. The bulb and socket are in good order, but unfortunately I did not test the circuit board before replacing the dash. :(