Car battery dead after sitting for a week- jumped. No problems running after that. One month later, same deal- wouldn't jump, tested- showed battery was okay. Finally jumped and ran. Again, no problems. Battery changed after car didn't start third time. Recently issues with security light coming on, turn signals randomly/sporadically working or not, and lights going off when switching from dim to bright [and then going back on]. Most recent issue is a fluctuation RPM when accelerating [no issue with gaining speed] and also a message to service traction system- it shut off and chimed. Car is not overheating, no other issues noted, and all issues are not occuring at one time. Ideas? Tips? How can I fix this?