Replaced battery and alternator but battery light is on

Your charging system is controlled by the power-train control module by way of a communication network. Many aftermarket alternators just flat out will not work at all because of the internal generators being the old style, I've replaced countless brand new aftermarket alternators for this issue! This could be one reason why it won't charge at fourteen volts. The proper way to diagnose this concern would be to retrieve the PCM codes, then perform a recommended pinpoint test for the code retrieved, but some simple checks can be done, like a voltage drop test between the battery positive terminal and both of the positive terminals at the alternator (should read less than 1 volt), verify proper voltage supply to the alternator, and verify good ground by hooking a jumper cable from the alternator case to a clean place on the frame.