So I've looked up this issue before, its actually how I learned about this forum but I never got a really clear answer. I've got a 2007 Yukon xl 6.2 and every once and while my headlights, dash, overhead lights, and any appliances I have plugged in will start to flash at a medium-fast pace like it's losing and gaining power. It will stop and start it never happens the whole ride and the lights or anything else never fully loses power. It started to happen more and more though, so I would like to get it fixed asap before I put in starlight lights in my headliner. and yes I've checked the battery connections I'm always connecting my battery and disconnecting it for projects. I think it might be my alternator, should I upgrade it to a more powerful alternator because I do have underflow( obviously unconnected when this issue is happening and all other appliances, radio is on though at full brightness ) but I just don't want to overflow the system and short anything or however that works lol. Thanks, Yall!