A/C coolant

It is almost impossible for a lay person to buy Freon 22 (used until about 2009) and 410(current coolant). Most States you must have a License to buy it. But, IF you need to charge because of no coolant, then there is a LEAK. They are solder sealed units and if you have a leak, then you must find the crack/hole in the system and seal it or replace the bad component and then add the fill valves and evacuate and recharge. This is not cost effective. So, you purchase a new upper unit. There could be lots of reasons your AC is not cooling that have nothing to do with the charge. You need to have it checked by a professional to find the cause. Doug

Not cooling

If you are referring to the roof top A/C as the "cabin air", they are generally not re-chargeable. There are no hookups for refilling them with coolant like a dash air would have. What do you think it need attention? Not cooling? Sometimes that is as simple as a good cleaning of the coils and change the A/C filter. Be a little more specific with your "problem" and type of A/C to receive better answers. Good luck!

Not the dash but the cabin air

Talking about the dash A/C?

Do you have gauges (high and low along with PSI charts for ambient temperatures) for the appropriate refrigerant (R12 or 134A) and the knowledge of your A/C system to use them? Is so, no problem.