heater controls not working

Recently my heater controls have not been working, at first speed 1 & 2 stopped working, sometimes i could turn the dial in between setting and this usually remedied the problem. Yesterday however the other 2 speeds no longer functioned. If i hold down the dial in a certain position the fan works again on hi, which tells me it's a control issue and not the heater itself. I would like 2 replace the part if there is no fix, are there any other car manufacturers that make something compatible to swap?
thank you for any suggestions