2006 Jeep Liberty Battery Drain

Over the past 18 months my battery has been going dead when I let it sit for 4 or 5 days. Today I installed my fourth new battery after getting it out of Dodge service. Dodge service ran diagnostics multiple times checking circuits for module leaks, but found nothing. When I got home from having my new battery installed, I pulled out my multi-meter and measured the volts in the new battery. The new battery measured 12.66v.
I removed the ground cable from the battery and attached the black lead from my multi-meter to the cable. I attached the red lead to the battery post. My multi-meter measured 12.66v. I began pulling one fuse at a time from the fuse panel (closing the door each time). The multiple-meter remained at 12.66v for each fuse except #3. Pulling fuse #3 (cigar lighter) dropped the multi-meter to 12.54v. Could this be the reason my battery is going dead every 4-5 days? Do you have any other suggestions?