SD connect C4 PCB rework for 24V 12V cars

Have any idea why SD connect C4 mux works only with 24V but no connection to 12V?
 Customer solution... Here you go.
Try on your own risk!
some of the NEC Chips are Broken 4 PCs and same the small board power chip i Change it and now they work on 12V too 

i change the first line from left side 
Replace the chip