A/C question

I have an A/C question. I am a novice mechanic and definitely know enough to get into trouble but have some basic A/C tools to work on it. I'm not sure how the A/C is suppost to work but the A/C is cool but not cold like it used to be. I wanted to add some some refridgerant to the system. The compressor seems to be working. I hear a click and the gauge climbs to 45 psi. It clicks again then the pressure falls to about 20-25 psi or so. Then it clicks again and pressure raises to 45 psi again. Is this normal behavior for the comprressor? Can i still add more refridgerant? Any help would be great.

Yeah, I just bought some recharging stuff last night and now you've got me wondering about this situation as well. Sorry I don't have an answer, but I'm looking for all the info I can get as well. I'll post anything I find pertinent.

If you purchased the recharge kit which i assume you did that is how the gauge works but to answer your question, the compressor should stay on and not cycle on and off real fast. Your system probably needs a little freon.

I just did mine. With the A/C off, it runs about 60-75 psi. with the A/C on it runs anywhere from 25-45 psi. depending on the temp outside I guess and/or how long the A/C has been on. They say to let it run for at least 3 minutes before checking. I added a can just for the hell of it. I didn't notice any difference really, but I'm sure the pressure is above what it's supposed to be. It was at 25 psi when I began. Now sometimes it's about 45 when you kick the A/C on and fluctuates between that and 25 psi. I'm not sure but I guess I'll leave it alone for now. The A/C isn't any colder really and the compressor still rattles like a machine gun. Oh well. POS Blazer to begin with.