The corrosion problem will show mostly when you are trying to start the car in cold weather if it all. Clean but if the connection is good there should not be a problem. Once the car is started it is running off the alternator so it shouldn't affect the blinker. If the blink indicator is going really fast then it is just a bad or loose bulb. Go to Autozone and by a two new ones if that is the case. Unless you are adverse to right turns the right bulb has had as much use as the left and could be close to failure as well. It really is simple to change bulbs and typically requires almost nothing in the way of tools.