I have the same problem and have been told its the heater fan has seized up draining all the power. Ive removed mine wich had seized up.
However untill i get a replacment i don't know if that is the problem. just removing it hasn't fixed the problem .
If I get any more info I will add it
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix cars.