A/C pump

[Tristan89xj]

how do you tell if your A/C pump still works so i dont refill it for nothing

[NW99XJ]

With the engine running, and the AC turned on....
Locate the Low Pressure switch.....
http://z.about.com/d/autorepair/1/0/a/a/42276757-a.gif

Short these two wires together with a jumper, and the compressor SHOULD kick on.

[Tristan89xj]

thank you very much it does work but only when i have the jumper wire is. im pretty sure thats not the way its sepost to work what should i look for to fix that

[NW99XJ]

Well that switch is meant to keep the system from running if the Freon (R134A) level is too low.
You'll end up burning up the AC pump if you do.
You'll want to have the system evacuated (a vacuum pulled on the system by a pump,)
http://www.harborfreight.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/i/m/image_18961.jpg

.....and left that way thru a set of gauges,
http://www.harborfreight.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/i/m/image_21674.jpg
...... to determine whether or not you have a leak in the system somewhere. If you dont, then at that point you refill the system with new refrigerant, and you're good to go.
But if you DO have a leak, some leak detection dye (which reacts to ultraviolet light) will have to be added in, the system ran for a brief moment to circulate, and then all of the hoses and fittings examined under a black light to locate the leak.
https://sphotos-a.xx.fbcdn.net/hphotos-ash4/p480x480/480407_486433631398833_1816024186_n.jpg

Obviously that line or fitting or whatever will have to be replaced, and the whole process started over to determine if that was the only leak, or if it was installed properly.
NOTE: There are many components to the A/C System, and any one or ALL of them CAN go bad. -this could get expensive if you take it to a shop.
If you just try and throw some "AC PRO" into the system without doing any of the other stuff, there's a good chance you 1.) wont get the proper amount of refrigerant in there, because the system is full of air.... and 2.) will most likely have to do it again in a few days or a week, as it will have all leaked out.
If you know someone in the refrigeration or HVAC business they should be able to help you out.
You could go to a shop, many places offer AC specials this time of year, OR.....
If you're technically inclined, you can get all the stuff you need (minus refrigerant) from your local Harbor Freight.
GAUGES - $59.99 (http://www.harborfreight.com/a-c-manifold-gauge-set-92649.html)
VACUUM PUMP - $104.99 (http://www.harborfreight.com/25-cfm-vacuum-pump-98076.html)