Two things happened at once. First I need to replace the battery (10 years old) on my 2011 GLK350 4Matic with 80K miles. Also just changed the ripped front seat cover, while doing this I disconnected the yellow plug on the front seat electronics. Now I have an SRS malfunction message I am sure was caused by either low battery or the disconnection of the circuit to the seat belt. Prepared to purchase the Car soft I980 OBD reader to reset SRS. What other faults will be induced by disconnecting the battery or what method is most useful and safe in protecting positive battery terminal from touchng ground if an auxillary battery is employed to save all codes and positioning sensors?