Why does my oil light come on when I stop?

Interesting. I suspect that either the sensor that monitors oil level needs to be replaced or you are low on oil. The oil in the sump moves forward when you break. If it exposes the sensor, it will turn on your low level light. Then, when you vehicle returns to its normal stance, the sensor tells the system you are OK and turns the light off again.Since you say your vehicle is full of oil, I would suspect the sensor is bad (but check the oil level one more time first).

If this is a high mileage vehicle I would suspect you're seeing the first symptom of worn bearings. Hook up a mechanical oil pressure gauge, for testing purposes, and see what yyour oil pressure really is. If it drops to nearly zero at idle once the engine is warmed up, it's most likely worn bearings. You can buy some time by using a heavier weight oil. But the engine is near the end of its life. Hope that helps! Jim