control change
With out knowing the specifics i.e A/C D/C and operating voltage it is a guess. However I'm sure it is quite easy.
If you send me the specs on the unit I will draw up a schematic for you. Don't know your level of electrical knowledge.
Send me what data you have and we can go from there. If you can do it your self that is great, just follow the schematic. If your reticent about doing it, I would be happy to do it for parts costs I would very roughly say 45 to 60 dollars. Once I see what I am dealing with I should be able to give a more accurate estimate.
Doug