Hi all,
I have a 2011 3.5 ecoboost that has some electrical gremlin that has me stumped. Using FORscan, I have been watching the various voltages creep up close to 17v across the battery and module sensors, which causes the truck to turn off the dash, radio, and HVAC system but the truck still runs. I suspected the voltage regulator and alternator but am now on the third replacement alternator with the issue remaining. The battery module has also been reset using FORscan but that didn't seem to make a difference. I have cleaned and inspected all of the grounds and connectors I could find for the charging system. I took the truck to two different parts stores and had two different styles of charging system carts tell me that it all checks out good. I am not sure what else to check short of going wire by wire through the harnesses looking for a bad wire. Any suggestions would be greatly appreciated.

Update: Truck started throwing data errors for the power steering module to PCM so I went looking for the power steering control module and stumbled on the root cause for my original issue (error for the power steering module seems linked to a broken ABS wheel sensor). The wiring harness coming from the alternator had a large tear in the loom along the bottom of the truck. The red/gray wire in that harness was nicked and corroded badly. After splicing in a new piece of wire, the problem is gone. All module voltages are reporting mid-13v range and battery voltage with the truck running is around 14.4v, much better than the previous 15-17v the truck was running at. So for anyone experiencing high system voltages and the instrument panel shutting off, check the wiring harness for the alternator carefully. Hopefully this helps anyone else having this problem as it was a daunting task to start running continuity tests on wires.

 

Just wanted to say welcome to FTE, and THANKS for posting the solution!