Ask a Mechanic Online and Get Answers to Your Car Questions
I have seen new alternators , starter motors fail . It sounds like your alternator may not be charging fully . start your engine and turn on your headlights . you would like to see 13-14 volts. also check that the belt is firm. you would be surprised that a loose belt can cause poor charging.
most electronics can run at 10 or so volts. your coils will not be happy about this so they start to breakdown.