The heater controls are inoperative. They are in a middle position. The levers both work, but when operated they spring back to the middle. The radio is out. Through the radio opening, both levers can be seen along with the cables and sheaths. Both air box trim panels' chrome fasteners are out. I would like to get those trim panels off to access the controls. Is there something else I need to do to remove the side trim panels? The old radio was an aftermarket, and the opening is enlarged. I am making a cover out of a piece of wood, but next, I would like to get the heater controls working.

 

I currently have the whole centre console out of my MK2 2.4 as I am fitting a modern radio in place of the old unrepairable valve job.( yeah I know its sacrilege but you can no longer get the valves and this is not a concourse car with a lot of mods including full synchro overdrive box, diff swapped from 4.29 to 3.77, SU HD6 1&3/4 inch carbies and 3.4 inlet manifold. For a 2.4 it boogies!

Once you have undone the side panel chrome fasteners, the panel is still kept in place by a lip down the bottom vertical edge.
Take the further edge of the panel (away from the driver) and move it outwards and towards the front of the car.
It should literally fall out.
You can then easily get to the air controls.

 

Thank you, Bill... Just in case, new cables are on the way. I haven't looked at the other end of the cables but that is next after getting at the controls.

 

You might find that the cables are ok but it is the flap and arm on the heater box that is stiff. Before removing the cables detach the cable from the side of the heater box under the bonnet and test if this moves freely. Water and dirt do get into the heater box and the foam seals deteriorate then break up and these can cause rust in the hinges and obstructions in the movement of the flap.

 

Some hinges on flaps can become extremely tight as you say Cass due to rust & difficulty in lubricating them. The Bowden cables are seldom the problem.

 

Good information all. Indeed the Bowden cables in the airbox look okay. Another electrical gremlin has appeared, so it will be a few days before I can report back. I made a wiring diagram compiled from several sources, including the tracing done so far.
Thanks for the help.