I was not truthful about the car's air conditioning
Why weren't you honest about the air conditioning?
The air in the car wasn't cool, I said it was cool because I'm a liar.
If you're selling a car, you need to be honest about any problems that the car has. If you're not honest, the buyers are likely to find out and become upset with you, and if the problem is serious they may even decide to press charges. Be open and honest about any problems with your car, that way you don't have problems in the future.
Lying gets me sales, though.
You are being unethical here. Lying to buyers is wrong, and it can and will get you in serious trouble.