Hello,
2008 Mariner Hybrid - engine battery not charging. (the LV 12v) Checked current at DC/DC Step-down inverter output it is showing 12v. All other systems seem to be working. Swapped out the DC/DC converter anyway, did not correct issue. Have to charge the battery at home each time I get back. 12v battery is new, only 2 months old, it was replaced because the other died, tested as a bad cell. Was hoping when I put the new one in the problem would correct the problem, but... not. The '08 does not have the 2 fuses at the positive terminal. I will pull fuse diagram and see if they relocated them in a box or if they ended up internal to the step-down converter, not sure of its internal logics? Terminals are clean, wires seem in good shape. was a southern Missouri car so has very little corrosion and little to no rust, even underbody.
Can you point me in another direction, all other electrical systems seem to be performing as specified.
Thanks,
Scott
You are now experience the reasons I tell people not to buy hybrid cars they are extremely complex. Now in a normal Mariner the alternator charges the battery the battery doesn't get charged it means the alternator is bad for the wiring between the alternator and the battery is bad. But you don't have an alternator you have an insane giant generator that goes through various systems that step it down to charge the 12 volt battery. I say you're going to have to break down and go to a hybrid specialist on that one if you don't want to try a Ford dealer
