Weird electrical problem...2006 Civic
 

My girlfriends sister has a 2006 Honda Civic 2dr coupe. For the pas year it has had some weird electrical problems.
-At first it just wasn't starting, so she replaced the battery, and it worked for about another month. Then it stopped starting up again.
-Next she took it to the dealership and they replaced the starter. It worked for a little longer and then wouldn't start up again. It sat in the driveway for 6 months bc she thought it was broken, but then I jump started the car and it worked fine.(I am under the impression that she might not really know how to jump start a car, even though she has done it successfully a few times.)
-----Now the weird part...after driving it for a few months; it started acting funny; occasionally when she would come to a stop while she was driving, her radio and A/C would lose power and turn off completely. And now it's back to not working at all.
-My guesses:
If it was the alternator, then the car wouldn't run at all since it has electric fuel injectors. Unless alternators can just get flaky?
I was thinking it could be a bad relay or loose connection on some wire. This seems like the most likely thing considering the weird problem with the radio and A/C.
-Also, she doesn't drive the car enough, because she is a stay at home mom.
I'm going to be down in her area this week and would like to take a look at it.

It sounds like there is insufficient output from the alternator, so the battery slowly drains down, and electrical stuff stops working due to low voltage. The fuel system is designed to operate on a low voltage, so it will be the last to stop working.

You should measure the voltage at the battery with the engine running. If it is less than 13.5 volts or so, there is a charging problem.

thanks
 

Thank you for your input; I just searched for "insufficient output from the alternator" and found tons of information and lots of other people with similar problems. Thank you very much!