Volvo Repair: 98 S70 100K A/C probl;em, volvo owners, compressor clutch

Question
My A/C has stopped working - I have the auto climate control which when I start the car shows orange flashing lights on the Recirc and Off buttons - When I run the A/C, I can hear a clicking noise as the compressor clutch engages and disengages every few seconds - Occasionally the A/C does cool, but not enough to cool the car - I picked up a recharge bottle at an auto parts store, and the pressure registered from 0 to 45 as the clutch engaged and disengaged - I doubt that tells you anything, but there it is anyway - Due to not being able to get any kind of reliable reading, I did not recharge the system - I suspect that could be the issue, but would appreciate your opinion - If I do need to recharge the system, can I reliabley do it myself, or must I rely on my local Volvo dealer - Thank you in advance for your help on this - You guys provide a great service for us Volvo owners

Answer
Warren, It is definately low on Refrigerant.  Most likely you have a leak in the Evaporator core.  Be prepared to pay about 1000 dollars for the repair.  Very labor intensive.   I would put a can in.  When you put the can in, pressure at idle should be at 45.  2500 RPM at 28.  Roger