There is a short circuit somewhere, probably from a damaged whire. It's also possible that the heater controll pannel is deffective.
You need to locate that damaged whire and replace it. In some cases, it may be simpler to simply disconnect, or cut out, the damaged whire from both ends and pass a new one, leaving the old whire in place.
Try disconnecting from the fuse box.
Electro
March 2013