cb12250

I don't have noises from any of the components, I just have lost heat now on and off - very strange. It works for a bit and then just blows cold air. Could this be the pump that was in an earlier reply? I love the diagram given, is this something that is a DIY thing or does it need to be taken in to a pro to fix? Any help or advice would be great. It is -5 at the moment and I really would like to have heat in my car.