Hello, i have a problem with mercedes glc 250 cdi 2016 it drained my battery once and when i tested it with multimeter i found it is not charging battery. I first changed voltage regulator then the whole alternator then the agm battery and still no charge, there is 0 trouble codes in ECU or SAM module I have 12 volts on B+ terminal and i checked continuity of terminal from alternator to ecu and its fine, every fuse is also fine i know it is ecu controlled alternator but i cant find the reason why is not charging please help