Newmember. The dreaded "Auxiliary Battery Malfunction" just showed up on my 2017 GLC43. I did a Google search and there doesn't seem to be any information on the actual location of the auxiliary battery for my car. I did see that Mercedes has put it in a large number of hiding spots, from front to back, on other models.
MercedesAMG GLC 43 4MATIC Coupe Premium​ specification. Where Somerset Price £53,880 On sale now Engine 2996cc six-cylinder twin turbo petrol Power 385bhp at 5500-6000rpm Torque 384lb ftBWT0.