A/C compressor seems to be cutting out - other things to check?

[othercarasaab]

My car is '06 sport, so manual climate control, heavy A/C user (almost always on 3 of 4 for fan speed, A/C on)

Basics: A/C started cutting out occasionally last week after pushing the car pretty hard in hills/mountains of Tennessee. Typically experienced 20 minutes into starting the car (but not every time), suddenly the air got warm comparable to A/C not being on at all even though A/C light is on.
The weird part is that in many instances, turning off entire Air system- fan to 0- for a minute, and then turn the system back on, A/C works for hours just fine on highway.

What I've troubleshot:
Radiator fan running fine
Radiator/condenser reasonably clean.
temp of both lines into condenser seem to be about the same, so don't think I'm low on freon.
Tonight, I was able to recreate where compressor cycles properly a few times, then doesn't turn on after that. - same thing where once I was able to get compressor to cycle once by turning system off/on, but then no compressor again...

Questions:
Anyone know where I could find electrical and mechanical diagrams of system?
Are there separate electronics for the A/C compressor/clutch, or is it all just one piece as the compressor?
A/C system access: is it easiest to remove tray and passenger wheel, or there a better way to access? (I have ramps or jack/stands)
Any likelihood that it's electrical/intermittent relay, or is it almost definitely compressor?

I'm reasonably competent DIY, but never worked with A/C specifically. Any other thoughts or things to check would be appreciated.

 

[othercarasaab]

Additional thought this morning...

Seems like when the system is warm is when I'm having issues. IF I turn off the entire system, and then restart, it is sometimes working...

could it be that clutch isn't engaging, perhaps getting stuck due to electrical overheating (Ie being told to engage but isn't, when cools after A/C off it can work again?) If so, is there anything I can do to try to fix a sticky clutch short of just replacing compressor? - this would probably be a generic question, I realize most haven't had to work on the A/C systems of their Mazda5 yet, relatively young car for A/C issues.

I realize I'm fishing here, but interested in anything I can look at/test before engaging in first major ($-wise) repair.

 

[flcruising]

...temp of both lines into condenser seem to be about the same, so don't think I'm low on freon.

Were you feeling them while the compressor was running?

You can do all the guessing at this that you want, but without hooking up a set of refrigerant gauges, it's all just a shot in the dark.

 

[othercarasaab]

Final diagnosis is a Black Swan.

I don't have refrigerant gauges, so I took it in to have a look just at a local tire place for an A/C check, and freon levels are fine.
The problem? Broken connector on the compressor, causing an intermittent electrical short. So we ripped off the connector, hard-wired, and all is fine. That's about the 10th most likely scenario in my mind, go figure.

 

[flcruising]

Good deal. Glad it was such a simple fix.

BTW, around here you can 'rent' gauges from any auto parts store.

 

[othercarasaab]

Tried to rent gauges here in Wisconsin, and 2 stores I went to said they can't rent them here.
There's pretty stringent regulations on environmental-type stuff by the state's Dept of Natural Resources (DNR).