I replaced the heater cables recently. Got a bit of schtick doing it in the middle of summer, but what better way to spend a sunny day than lying under your kombi getting covered in grease and dirt!
The passenger side came out with a bit of effort and the new one went in ok with grease on it. The drivers side was a different story. The cable outer came apart like a big spring. I ended up having to cut the metal conduit to get the rest out. I also had problems getting bits of the cable plastic sheath out of the conduit. The best method I found was to use the springy bits of the cable outer like a big corkscrew!
Cutting the conduit also made it easier to get the new drivers side cable in because it stuck at the point where the conduit is tack welded and has rusted inside.
I also needed the cable that operates the flap for the lower vent. Apparently these are NLA. If you need one you can make one out of the old heater cable as you only need a short length for this cable and you should be able to get a usable section of the heater cable. The only problem I had is that the heater cable is thinner so I had to pack it with a piece of metal where it clips to the flap.