Changed battery and I am having other control problems

I went to Advance Auto to replace the original battery on my 2011 Nissan Frontier SV 4 wd v6. They plugged in a box into the OBI 2 port. Changed the battery but the positive wasn't tight and when we went to check it pinged and wouldn't start. He took off the positive and retightened. The truck started, but the blower motor was on full and couldn't be controlled. The gauges do not initially work well but after a few seconds they work. Also some small things didn't work, open door alarm, ect. They then changed the fusible link on the positive cable, no change. If you use the power pack on the OBD2 port everything works fine. Remove it and the problems show. What could be the problem? - fuse somewhere to OBD2 port? Looked at all 3 fuse box locations and they seemed fine.