Weird situation. I have a 20011 Yukon Denali. I had the drivers side brake light bulb burn out. I bought new ones and went to replace the burnt out bulb. Swapped the bulb then went to start the car and it acted like the battery was about dead. So I hook up the charger and let it sit for awhile and try to start again and it just barely cranks once. Then dead again. I put the burned out bulb back it, put it back on the charger and everything has been just fine. I tossed the bulb I had originally swapped in but it came in a two pack. I installed the other one today and the car has started but it defenitly us having a tough time turning over. Any ideas??