I just connected an oil pressure gauge and sender and the light worked fine for a couple days and now it does not go on at all? What voltage should I be seeing at the two leads?

Turn the key on and ground the wire for the light, right at the sender. ZIf the light comes on, then you have a sender problem. If not, you have a problem after the sender. Then you check the bulb, followed by the wire. The Cap'n