I have a 2009 Mazda 6 that I think needs the battery changed.This is one of those types of keys where the key itself will fold up in to the key itself and then pop out like a pocket knife when you are ready to use it. Everytime I try to use it the functions do not work but they will work if I open or close them manually, pluse between the lock and the unlock button there is a little bar and everytime I push on of the button this little bar lights up red. How do I change the battery and do I need to do anything else after I change it?