John,

When the connector to the P-lead wire at one mag was installed and the P-lead Shield was stripped, the cut went through the P-lead insulation.  It didn’t show up for about 300 hours until it started intermittently shorting for about 1 minute then it would be OK for hours.  Mucho time checking/testing went into that one.  The wire had to be moved just right to short.   

Steve Colwell  Legacy 550

But this saga isn't over yet, because I checked the right mag and it reads open at the P-lead terminal. To be continued...