I don't know if this is the correct place to post this, so I'm sorry if it is misplaced. I was searching for forums with people who would have some knowledge about my car and weed out responses from people just taking a guess.
I bought my 2003 Toyota Matrix XRS used this past March from a licensed resale dealer with signed contracts, warrantes, repair reports, the whole nine yards...in other words I didn't purchase my vehicle from someone selling on craigslist with no knowledge of the condition of the car. When I was testing it out I included testing the ac and heating and found them to both be working well. It was spring at the time and the AC blew cold air and I was satisfied.
Once it started getting hotter outside and I used the AC more often, I noticed that the hotter it got outside made it harder for the AC to keep the air cool. After a couple of months I then noticed that it would get luque warm then blow cooler every so often. Few more months later it's progressed to cooling the air less and less until it completely cut out during a drive a month ago.
I tested the compressor by idling with it on the coldest setting at fullblast with the AC button on. It turned on and off with me switching the AC on and off, so I figured the compressor was working correctly. I then thought that maybe the freon needed to be recharged and bought a can that came with a pressure gauge, which measured it being a little low.
Since I bought it used with only one previous owner I figured that the freon in the line hadn't been touched since the car was made. I emptied out most of the freon with the AC running on low and then followed the instructions on the can to replace the lube and charged it until the pressure levels read correctly. After I did this the air in my car blew extremely cold but on the drive back to my house it slowly got warmer until it was blowing hot again. When I got home I checked the pressures again and it then measured a little high. I released some pressure from the lines, waited and checked that it was then at the correct pressure. The next few times I drove it, it acted the same way it did before it was charged except it now blows extremely cold air when it does turn on.
The compressor still turns on and off when I switch the AC on and off. This past month after it was charged the times it's blowing cooled air I paid attention to how cold it was and it hasn't gotten weaker. This makes me think that it isn't a leak because I would expect it to slowly get weaker like it had previously. I have also noticed that if it starts blowing cold while the car is idling it sounds stressed as if it were trying to die but it hasn't effected how the car drives when I'm giving it gas. I've also noticed a strange smell when it is blowing cooled air, but I suspect this is only because it was just charged. I'm mentioning it though because I'm not sure.
In asking in forums I've had a few people mention that it might be a control switch, and in searching I believe they mean either this switch:
or this switch:
I'm 21 and Female so unfortunately after taking it to 3 different mechanics I've gotten 3 completely different answers, all of which are really expensive. I don't want to be taken advantage of, and given that it does still put out cooled air tells me that it is probably a small electrical/sensor part that has gone bad.
Thanks for any help or advice I get from you guys, and hopefully I can get this done with inexpensively.