Search for UNLOCK OBC. Lower case. Most likely the instructions you find, will tell you which test is to monitor voltage. You unlock OBC once, its stays unlocked. You can monitor your voltage when driving. If it isn't around 13-14V, your alternator is effed up. I am thinking voltage regulator by the way. But you need to do the above test first.

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2006 4.8is, Black on White. SOLD Sniff Sniff.

2017 F85 x5m, Black on Red. BEAST MODE


"The older we grow the greater becomes our wonder at how much ignorance one can contain without bursting one's clothes." - Mark Twain

Unlock OBC post 5