The problem- The a/c comes on, cools great for about 3-5 minutes, then blows warm air. It may start back, sometimes, after about 10 minutes. It will sit at idle for an unlimited amount of time blowing cool air, but when it is idled up it stops. What I've done so far- Went to the dealer (the only people in my area that work on a/c) and they said it needed servicing ($145.00). Did the same thing. Then they said the low pressure switch was bad ($75.00). Did the same thing. Then they said the fan clutch was bad ($175.00). Still did the same thing. Now they say the compressor is bad (they want $1500.00 for that). They told me about an electro-magnetic switch in the compressor that is 'probably' bad. When it is hooked up to gauges (I don't remember the exact readings) the low side remained steady and the high side dropped after reaching high idle. I don't have access to gauges but if needed I will plop down $$$ for them. Any ideas? It has been suggested to try recharging with a can of R134. I can try that (I have a can of it and a hose) but I cannot tell which outlet is the low pressure side. Any help is appreciated.

i would like to know how to change my gas filter on frame? i need to know how to de presure my sestum to change filter. and if i need a tool to take filter off, or just pull?