Virgil,
Don’t listen to the naysayers. I like the way you think.
Like only ten thousand other people, my 2013 C-Max has the F79 circuit drain problem. I recently brought to Fox Ford in Chicago where ($165 diagnostic fee later) I was assured the problem was a loose cable on the battery and not a drain. Less than 2 days later, dead again. Grr.
In the past, the radio failing to turn off was the symptom which told me to pull the F79 fuse and allow the system to reset. But in my car, apparently, that no longer is a reliable indicator of when the drain is occurring.
If the dealer promises to make a genuine effort and read the service bulletins, perhaps I will bring back. But just in case, I am kluging together my own solution –
Splice a cut-off switch and ammeter into a fuse extension. Anytime I see current flowing after the car is turned off, I will open the switch and (hopefully) allow the system to reset.
