if its not the battery the line contactor is probably not closing all the way or tips are bad. to check it remove the right side cover, turn the key on and reach in and push the contactor...if it moves and locks in you could have a cpu problem, it pulls in at battery voltage then drops to a much lower voltage to hold. if it misses the first part of that process it wont pull in tight. if it doesnt move replace the contact tips. if it does.....get your wallet off of it's leash. i can give you some options if you are handy with soldering iron and pc perf board.