I am very sorry your having this issue with your vehicle.
I will try my best to answer all of your questions.
However, before we get started, please let me mention a few things.
1. If at any point you would like to speak on the phone, please feel free to request a phone call on your end and I can call you right away.
2. If you dont understand any technical terms or anything that I mention (component tests or theory or operation), please let me know and I will provide you with a more in debt explanation or answer.
3. Please understand that I am here to help you any way I can.
YES, hands down the oil must be changed first. This may or may not be related (although I suspect it is), it would be silly to go after an electrical issue and replace any electrical component if the engine just simply needs an oil change.
I have a feeling once the oil has been replaced, the oil light will no longer flash. :)