car working fine one day the next day does not start, no light to horn no dash on 2006 Jeep Grand Cherokee

no dash lights no battery click, when jump started all is good battery tested at 98%Help repair shop said they do not know they cannot duplicate the problem

First battery must be charged and load tested for at least 30 minutes. A battery that is 3 years or older may develop a bad cell, creating this kind of problem. Get battery tested at a repair shop close to your location.
the battery is 18 months onld and advance did a load test for this and thats how i knew the info