There's too may things that require a visual inspection, but I can offer some suggestions for the "Battery" light. When it turns off periodically, there is not a permanent failure, ... Yet, and it can go like that for weeks or months, but what is important is any testing of the charging system must be done while the problem is occurring, meaning while the warning light is on. When the light goes off, there is no defect at that time, so no problem will be found.
The most common cause of intermittent charging system operation is worn brushes inside the generator, especially at the mileage you listed. There can be intermittent wiring connections too, but those are much less common.
As for the "Oil" light, that is referring to low engine oil pressure, not level. Your mechanic can use a mechanical gauge to check the actual pressure. If that is good, the oil pressure sending unit, (sensor) is the typical suspect.
Tuesday, August 25th, 2020 AT 12:06 PM