2001 f150 has new alternator & battrey but wont charge battery light stays on will go off at 3500 rpm
This system is computer controller, so you will need to take it too someone that knows this system that can diagnosis it properly, could be anything from a bad ground, to an all out failure in the ECM.
These trucks are regulated by the pcm, I've seen it happen but as said above I'd get it looked at by a professional before jumping to that. The pcm will need to be programed anyway if that's the case
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