[BigHornHemi05]

I have a Ram 1500 5.7l hemi with approximately 140k miles. The A/C stopped blowing cold air. I was told by a mechanic friend of mine that if my a/c system does not have any/enough refrigerant in it then the compressor clutch will not engage. (which it doesn't) Would it be worth the $39.99 to by the a/c recharge kit from an Auto Zone, or O'Reilly's? Or should I take a different approach. I do not want to take my truck in anywhere to have it worked on, I enjoy working on my own Truck.

 

[Cornfed2009]

Either your refrigerant is low or your compressor is bad. I don't know if the clutch disables with low refrigerant, that doesn't make sense entirely. However if you "run your a/c at max cold and max blower with the doors open you can check if the clutch engages by an audible click, and check your refrigerant level on either side of the evaporator. The fixed orifice side of the evaporator should be much colder than the hose leading to the condenser". (Haynes Manual Ch.3)

 

[Moparite]

You may want to post in the correct place. This is...
1ST Generation Dodge Ram – 1993 & Older Dodge Ram Trucks

But to answer your question, Yes. There are both low and high cut out pressure switches. Not enough or to much will cut out the compressor from coming on. But there may be other reasons why it's not working.

 

[Cornfed2009]

To answer your question, once you have determined the outcome is low refrigerant, then I would buy the recharge kit from the local auto parts store. Looking around Auto Zone the other day, they even have pamphlets about how to properly check and add refrigerant.