The outercasing of on of my heater cables is broken, so the whole thing moves instead of just the wire so. To get the cable to work i will need to replace the whole outer casing of the heater cable. Has anyone done this? Is it hard? Expensive?

If you mean the sheath that the inner cable moves in, it comes with the new cable. If it is the tube welded to the floor pan, it needs to be welded back in place.

I have replaced heatercables on both our old bus and the current one, both 75 models. I did it on a hoist both times as it is a bit of a bugger otherwise. The first one had a cable that was fully rusted/ seized/ full of dirt and I was lucky not to break it inside the tube. Yours is moving inside the tube I think, so it should come out ok.

I think I paid about $35 per cable about 4 years ago. 2 required to go to the back

Sounds possibly like the ends of the outer casing are not fixed in position properly. Each end needs to be fixed for it all to work.

Yea, the sheath is broken on one of the cables, but the others are really tired, just moving. So new heater cables come with the sheath and everything? Where should i go to get the cables and outer sheath?