Most cars need to have low pressure code cleared before compressor will engage. Some folks cheat by removing PCM fuse or disconnect battery to reset code. That may or may not work on your car. It does sound like you have low system pressure if adding freon before helped performance. But, you might have a tiny leak in condenser last yr which now is bigger? Usually leaks get worse over time, not better. It's common for front mounted condensers to have road debris damage.

Thanks, cavell, are you saying there may be an error code that can be read with the "code reader"? I can stop by my friendly auto parts store to get the code read. I do not have any display - such as engine warning, that may be the only display sent to the driver.

Most likely, your A/C system has a leak and you'll not have a successful repair until the leak is fixed.

I had the same experience last year with my 1998 Jeep. The local Firestone shop that was equipped to service auto air conditioners when over my unit with a 'sniffer' to find the leak. They thought it was the fill valve and replaced it and re-charged the system. It worked well for one month and quit again. The symptoms point to a leak and low refrigerant. In other words, it is still leaking. The low pressure switch is open and keeping the compressor from running.

The system can leak anywhere. Typical places are at connectors, hoses, condenser radiator, and the compressor.

I suggest that you take you vehicle to a shop that is equipped to service auto air conditioners and have them go over it with a leak detecter. After the repair and refill, request they run the leak test again because there can be more than one leak.

Yep, a leak I put a 10 oz can in last July 3, and the system worked fine all the rest of that summer. That time the A/C was just low, not "too low" and it was still cooling, just not as much as it should. The additional (without gauge) refrigerant brought the delta Temp up to specs.

The trouble shooting of no clutch engagement led me to just add another 10 oz can to see what happens. The engine was running with the A/C switch "on" and it took only 10 seconds of the fill (these cans can take up to 10 minutes to empty on a nearly full system) for the clutch to engage and about 3 or 4 minutes to empty the can. I'll let it run this way for a few days and see what happens (it is cool here in NJ right now - in low 40s this morning). If it holds for a week I'll just top off using a guage and some anti leak. If I can get the car through the hot weather of 2013 for under $50 invested, I'll take it and worry abvut next summer if the car and I are both still around. Both of "us" are Senior Citizens.

Up to 2009 I had always taken my purchased new cars to a shop to have the A/C serviced. I have kept all cars purchased new for at least 10 years, the 2004 is obviously coming up on 10 years - so new car is on the possible solution list. A 1999 Mazda was my first time adding refrigerant myself, it worked out fine there too - also just added a can to increase cooling, and it worked. I traded that car in before much of a test on the pump-up, but I did keep that car through that summer that I added the refrigerant.

No stop leak stuff please. I do not like the thought of sealer stuff in a/c systems. If a a/c tech chimes in and says ok, than you can do so. But than he wants to replace your whole a/c system next. Maybe I am biased?

The 10 oz can put in April 22, had no additives, not even lubricant, which troubled me some. This was done without the benefit of a pressure gauge but the system was so low there was little likelihood that it was overfilled.

This was followed up about a week later using an 18 oz can of the stuff with both stop leak and lubricant, and a low pressure side gauge. I estimate it took about 1/3 of this can to bring the low pressure up to spec.

The system has been used several days since, including by me yesterday, and all seems well (it was in the low 80 in NJ yesterday - and humid).

As for no stop leak, it takes a special order to get such and it may be the "stop leak" in the more popular (market leader?) brand is more a seal conditioner than a hole plug. I find it hard to believe the leading supplier(s) of DIY refrigerant would sell stuff that would invite law suit... the lawyers lover "class action" suites, then even if the individual claims average only a few hundred or a thousand dollars, in aggregate we're talking about millions for a widely sold product. But, for this to payoff the layers will have to find thousands of claimants and from the warnings about stop leak I've seen here and elsewhere (not a consensus I will add) there should be thousands out there, not one of which has posted here to lament their experience.