Ok so I used to have my dvd player running off of accessory power by tapping into the lines that ran into my RNS-E.. I occasionally had turning signals going out for a couple of days then magically working again..Was told the socket needed to be replaced, but put it off.. My car would also struggle to start occasionally, it would just hang and then stall on startup..But then startup right away on the next try..This made me somewhat more concerned.. Then I didnt use my car for a weekend only to come back to it with the battery drained. Same thing happened everytime If I hadnt driven the car the day before. So I finally decided to disconnect the dvd player for the time being, and have it professionally installed later. Shortly afterwards I noticed all these problems dissappeared.. Lights were fine, car always started smoothly.. Well this past weekend I was taking a long road trip and wanted to hook up the dvd player just for the weekend at least, so I did.. Within 4 hours of it being connected, the front right turn signal goes out.. and the following morning I get the starting problem.. So obviously i disconnected it again.. but wtf is going on? Im more concerned about the struggling startups. What are the common causes for something like that?

 

My guess is for the starting problems you have a bad ground/power connection at the battery or the chassis thats preventing the starter from getting its power flow, i had a problem with my stereo amp in my S-10 that would cause the starter to just click every now and then.
As for the blinker problem, that is completely not related, it does need the electrical sockets the bulb sits in. Next time it acts up tap on the fender and you will notice the bulb turn on magically!