I have a volt meter installed in my dash, and I notice that when I start the car it fires right up but the interior lights stay dim and volt meter reads low in the orange. As soon as I rev the engine up above about 2800 rpm or so the volt meter needle reads normal and all the lights brighten. I'm assuming this is an alternator issue? This is a development of the last few days and I did clean some corrosion on the alternator contacts a few weeks ago.