I couldn't find any threads on this and I just noticed it. I was BSing with a friend of mine showing off my AV and I turned on the dome light manually via the thumb wheel on the dash so he could see the interior. I noticed the dome light was pulsing / flickering slightly like there was a bad connection or bulb
. The truck was running and in gear. I put it in park, still slightly flickering and when I shut the engine off it stopped. The light is bright and steady. The voltmeter look normal and everything else looks fine. I started it up and the same thing happened when I turned the light on with the engine running.
Anyone got any ideas? 

