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Hello all,
I have a 2011 F250 SD 6.7L 4wd Reg Cab XLT. I’ve had it since about 70k. Recently Alternator crapped out. I’m a Mercedes-Benz master tech, and also have certifications for Lexus, Honda, and Porsche. I think I still have some ASEs floating around too. I’m humble and don’t like not knowing things. Lol!

To get started I verified the alternator was done. No output, correct voltages at connector from pcm. Called ford a week out with an alternator, so that was a no go. Did some looking online found a 200a option for my truck. Went thru build sheet found and verified engine in my truck was pre-wired for hd dual alternators and extra hd single alternator. So wiring is good. I know Aftermarket stuff is junk, but I thought I’d be ok with NAPA. First one showed up with broken electrical connector, second showed up looked ok. Installed, regulator is garbage. Spiking to 15.2v at idle, pcm flips out and shuts alternator down, voltage drops to 13.2v.
Get third one coming. Swap third alternator, only charging to 13.4-5v at idle 14.6-7 off idle. Battery light comes on if truck idles for over 6-7mins.

In this forum I found a thread about some trucks needing to be flashed to go from single to dual alts. My question is, “do I have to flash my pcm to go from hd (157a) to extra hd alternator (200-215a)? Or am I just looking at a fourth and final straw crap aftermarket alternator?”
 

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I'd be willing to bet there is a PCM/BCM programming to use the higher Amp alternator correctly.
 

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Took a look at the Forescan AS-Built data and did not see anything related to the alternator settings. So if there is a setting it would be in the PCM.
 
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