Hey dm, I'm assuming this is a RT, but the truck cranes use similar systems.
The hunter heaters are a little box, self contained, under the seat. They are propane, and have the bottle (like for a grill) mounted behind the cab, and there will be a exhaust pipe out the bottom of the cab. There is either a toggle switch on the box, or on the dash, for ignite and then run. If you have a "hunter" its not A/C. If its a hydraulic heater with A/C, or just A/C, they have a big box outside the cab with a hydraulic motor in it that drives a compressor with belts. It will also have a external condenser (looks like a radiator) with lines that come from the hydraulicly driven compressor. Don't confuse the A/C with a oil cooler, which some of the Groves also have upstairs. Some of the Grove's use hot engine water for the heat in the upper, you can tell if its that because you will have lines from your radiator and engine carrying hot water up through the swivel and then to the upper. I've run some that use the hot water for heat and then also have a A/C system upstairs. Take some pictures of what you have in the cab, and what there is for boxes on each side of the upper, behind the cabs and we can probably identify what it's got.
Bad news, if it does have A/C, but its not working, it can be $ to fix, especially if it hasn't worked in a while. It may just be low on freon, then the low pressure switch is making it not work, then $15.00 at napa and you will be chillin. If its big $, the boss may tell you to just open the windows. Or the mechanic may be too busy fixing non working equipment to mess with your A/C (he doesn't have A/C why should you?).
I'm not really a big fan of the hydraulic drive A/C systems, they really heat the hyd oil, and rob power from a function when running. They are real bad about heating the oil, if your running a lot of cycle work, with all of the boom out. You end up with very little oil in the tank, and if your hyd. cooler is hydraulic drive too, you just can't get ahead of the heat. In 100deg. + weather with the A/C cranked on a 70 ton I used to run, you needed to pull the boom back in after about three or four hours of work, to bring some cool oil back to the system. So if it's really hot, and you do get to running the A/C, watch the hydraulic temps, because you can really cook a system.
There are also some aftermarket A/C systems that are direct drive hydraulic compressors, but then you wouldn't have switch on the dash.
Hope this helps a little, post some pics and maybe I can help a little more.
