[Ryan685]

The freon pressure is low. It doesn't mean it's empty though. There is a pressure switch in the system that will not allow the compressor to kick on if the freon is low. A shop may or may not charge the system back up if it has a leak. They will want to repair the leak, probably an O-ring somewhere. Worce case for leaks is a compressor seal or worce, an evaporator or condensor. One is inside the dash, the other is in front of the radiator and looks like a radiator. Leaks usually have oil around them from the freon to kind of show you where it's leaking. Leaks are very slow sometimes. Maybe a month or more to get low enough to cause what you are seeing at this time. Your best bet is to ask the neighborhood shadetree mechanic to add a can of freon to get you through the month. He will need to know something about air-conditioning, like if your truck takes 134a freon or R12. Not everyone can buy R12 because they stopped making it, it's a danger to the ozone layer around our plannet. R12 is about $65.00 a can or more depending. 134a is around $10.00 a can. I can't say if '93 has 134a or R12. You can't mix the two because of different fittings for the two freons. If you take it too a shop and your truck has R12. R12 has to be "recovered". Meaning they take out the freon from your trucks system and save it instead of just releasing it into the atmosphere. Then they repair the leak, draw the system down to get as much air out of the system as possible . Then charge it back up. All that for about $1000.00+. By law they have to repair a leaking system. Anyway, that's most likely what's wrong. It's low on freon so the hi/low switch won't let the compressor come on.