Alright so I just bought my grand fathers 74 Nova from him and noticed it had a factory AC and heater on it. Last Winter I would use the defog/heater but noticed it only worked on Low/medium fan speed. This year I'm looking to use her more and noticed that I have no fan operation at all. I was just wondering where should I start to trouble shoot both issues? The fact that it doesnt turn on anymore at all and why only some speeds worked and some didnt? Any help would be appreciated.