‘02 LS Severe electrical gremlin

prometheusLS

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kokomo indiana
(Quick summary: possible internal PCM Issues? Overcharging/ lights shutting off when driving)
I’ve got an ‘02 LS sport. November ‘24 my alternator died, second one I’ve put on the car since owning. then December ‘24 my battery also died. Kept getting a check charging system light after the battery was replaced but no major issues arose. Roughly 6 months after the alternator was replaced I was heading to work and the alternator died while driving and I had to run on the battery to get home. HVAC controls, message center, dash and a louder vacuum issues in the engine bay occurred. Got the alternator replaced again and it started having frequent power surges and overcharging issues. The alternator was warrantied again incase it was bad however the issues were still showing randomly. Progressively getting worse. At times at idle the battery read 16.4V. If bad enough my deck speakers, HVAC, dash, message center and even all lights on the car would black out until it I cycled the key back to accessory. No issues at all in accessory. And I the car still runs and drives fine, i was around 6k rpm doing some sporty driving heading home one day and swear I saw a flash from the front passenger engine bay and the car shut off. Pulled over and it started again fine but my odometer read “- - - -“ and speedo doesn’t work. It’ll cycle but not read. When the battery is disconnected and reconnected the odo will show the mileage it stoped recording at “174k” for roughly 2 seconds then return to “- - - -“ I’m assuming it’s internal PCM related, no visible corrosion or burn marks, all grounds were taken off and cleaned when I dropped the front subframe. any ideas? I have a new pcm on standby vin matched and programmed but I’d like to get more input. Lincoln dealer wants $650 to just install and program a key which is why I ask here first. The car is over 185k miles now and has been good to me, I just can’t pinpoint the issues. Thank yall for the help.
 

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