Heater Control

I plan on making an electronic control box so that I can alter the heat coming out of the ceramic heater element. I may be suffering under a delusion that I can get too much heat but it is almost as easy to make it variable as it is to have just on and off.
Here is the original cable-operated control. The cable goes to the hot-water tap under the bonnet - which no longer exists. The other (lower) cable is the vent control and the choke cable is on the left of the photo.
I'm kind of looking forward to losing three out of the four cables that connect to the dashboard. The speedo, choke and heater tap cables are gone. Pulling the dash out is going to be dead easy in this car.

Here is my new control. The linkage now goes to a potentiometer with about 120 degrees of rotation. The pot gives me 0 to 8K Ohms variable resistance which will be the input to the heater variable control box (PWM control). The pot is mounted on a piece of aluminium which is held using the old cable outer sheath securing bolt.

For the technically minded, the little pieces of linkage metal are from the strain relief of a DB25 connector I had lying around at work. One vice and a pair of pliers...
I will seal up the gaps in the pot before installing it to ensure that dust doesn't cause problems.