Ok, I'm having the weirdest issues with ny '04 SF. Not that I'm complaining cause the car drive great, but here is the rundown:

This past winter I've noticed that when my cliate controls were set to any setting located on the right side of the dial, my AC compressor would engage from time to time even though the AC was clearly turned off. I was frustrated and basically decided to just use the options on the left side of the dial.

No, I turned my AC on and I heard the compressor engaging, I ot cold air. I turned it off, and then after a while turned it On again..this time nothing...weird...so I turned the AC off and on again and it engaged.

Lately it will not turn on at all. Now I'm stuck between this being an electrical issue (mainly due to the fact that the think was turning on by itself during winter season when clearly I had the heat cranked up all the way), or the compressor went bad.

Any body have any ideas what could be wrong?

I'm starting to wonder if perhaps I did something when installing my car stereo.

 

So I've checked and double checked everything I possibly could and I have a firm belief that the AC compressor is the culprit. I'll be really pissed of when i replace it and it still does not work...

 

So are you sure the compressor is getting power to the clutch?

 

Do you have the manual or automatic controls?

I ask because my Tucson started acting up about a year ago. I'd be driving along and the blower fan would just shut off. A second or two later, sometimes longer, it would kick back on. When it was quite I could hear the relay clicking off and back on. I checked the fan, I checked the relay, I checked the power supply, nothing fixed the problem. After a few months I got pissed off enough that I started searching eBay for a used controls set. I pulled the center dash appart and removed the old controls and installed the used one from eBay. The problem has never returned. I could have gotten a new one from the dealer under warranty but I didn't know if that was the problem and because the problem was erratic, I was afraid it wouldn't act up when I took it in (plus, I'd rather do the work myself).

So my advice is to have a dealer check the controls themeselves. I'm not sure if that is the probelm but it was for me.

 

So I kind of was browsing the hmaservice information on the cooling system and it got me thinking perhaps the pressure has dropped in the system and the AC will just not engage. Went out and bought a set (lucky me it was on sale so I spent $100)...I know here in Canada it's twice as expensive but what can you du it's either that or fork out $800 for the mechanic.
I hooked up the gauges to the High and Low pressure points and guala...The Low pressure side was reading off the chart while the High pressure side was fairly low. As per the troubleshooting in hmaservice, this scenario constitutes a bad compressor (the thing will just not engage). I'm crossing my fingers I'm right. If I am I just need to swap the compressor, won't even have to pay for refil as the AC refrigirant can be harvested.
I'll update as soon as i swap the parts...Anybody know of a good place where I can order an AC compressor via a website with fast shipping to Canada beside ebay? I got time until the end of the month before our family trip....

Thanks,....
Pete