JoeS wrote:Thank you all for your suggestions. So, my friend cleaned up the 12v battery terminals and reseated all the fuses and removed a bunch of junk off his wife's keychain and we'll see what happens before proceeding with phb10186's suggestions ... so far, no news is good news.
Joe - I should probably add that if any of the stuff I mentioned overloaded it would likely blow a fuse, especially the AC stuff - though difficult to say if there is internal overload protection on those motors respectively (which there may well be, not studied any wiring diagrams on the i)... hence my suggestion. If that was the case. then you could potentially have, for example, the AC compressor stopping, perhaps shutting the car off - even though the fuse doesn't blow. However, I cant see that total loss of power would be intelligent by design there, so I am less drawn to those items.
That said, you are absolutely right to check the simple stuff first, as the 12v battery is very likely to be the culprit.
One last bit of anecdote, as Sandage also reported, years and years ago I had a Mazda Protege (323), which had a faulty ignition switch that was causing both intermittent total shut-off and intermittent engagement of the starter while the engine was on, and that was a very low cost fix. That could be another thing to look at if all else fails, I had fun isolating that one - but it does switch the entire 12v side on and off, so may be worth a look.