why does Air Conditioning go off when I turn the speed control up to 3 or 4?

Hello, there is no correlation between fan speed and compressor operation for the air conditioning system. So, I'm not sure what you are meaning by "a/c shuts off but still blows air". If you mean the air isn't as cold with higher fan speeds, then that's probably evidence of the system not being able to generate cold enough air in the refrigerant system itself, or with the climate control temperature blending inside the vehicle. Hands on testing is needed to check all parts of the system -- under the hood and inside the vehicle. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops