I turned my A/C on for the first time today since I had my headers and mids installed about 2 weeks ago. I can tell the unit is engaged with I turn the knob but it's not blowing cold. Could they have done something to it when installing the exhaust? I know alot of stuff has to be disconnected to install the headers but wasn't sure if any was A/C realted. Other than that, what else could it be? Coolant leak?