Well I've had so many different flat iron over time, and it seems to me the best thing to do is get rid of that iron all together and get a chi iron . These specific irons in my opinion are the best i ever had and will last for years. I currently have a chi flat iron now and this will be my 5th year owning it. And they get hot very quickly unlike those other brands where you have to wait like 15 to 20 minutes. But with the chi I wait maybe 2 minutes max before its to my ideal level. The only part that sucks is the $$$. The usually are over a $100 but I'm telling you it's worth it...
I have had this problem too. It could possibly be the battery post aka the part where you would put the jumper cables. There could be rust build up around them, and may just need a good cleaning of taking the rust off around them. I'm having issues with my battery too, so I feel your frustration. Good luck too you and if you could, let me know if you figured it out... Thanks :) Ladyvans