I have just purchased a minty 1990 scsb K1500 with 54000 miles,. It has the dreaded digital heater control with servos to activate the doors. Most of it works. Vent , temp both go up and down as normal. the indicator shows what the system is doing. Are these even available to buy any more? The switch doesn't do anything when i push the defrost button. It stays on floor. The indicator also doesn't change just shows floor. Has anyone swapped one of the manual heater controls in ? Cables and levers. Will the cable control fit in where the digital one is? That would be so much more simpler to deal with.