We live in a woodsy area. Yesterday I surprised a woodchuck or groundhog who promptly ran into the engine compartment of my Ford truck. I've seen him near the house several times. I popped the hood and poked him with a stick trying to get him to run back into the woods. He ran out right into the engine bay of my 2005 Malibu parked beside it. He must have preferred Chevy's cus he would not leave. I kept chasing him with my stick and he kept moving around in and under the Malibu. I even started it and rocked it a little and he stayed. I didn't want to kill it so I didn't drive off. After about 20 minutes of being constantly hassled by me and my stick, he finally ran off.
Today my A/C doesn't work. I looked for wires off or damaged but couldn't find anything. Some insulation was frayed on 1 wire going to a pressure switch, but the wire looked intact. The switch is on the high pressure side and has 3 wires going to it. The A/c light comes on indicating A/C on. The compressor clutch does not engage. The clutch fuse is ok. The pressure on the low side tap is 100psi, so it's not lost it's R134. I couldn't find any other pressure switches or a accumulator. That's all I know so far. Tomorrow I'll go the the library and get on their Alldata service and see what I can learn.

With the A/C on, the 2-wire connector for the compressor should carry 12V and ground.

If that checks out (as in no power to the compressor), then, next is the the refrigerant pressure sensor (your 3-wire switch, actually a pressure transducer). Two of the wires carry the 5V supply and low reference signal (~0.1V) from the ECM, respectively. The third wire is the input to the ECM and carries refrigerant pressure signal (between 0.1V and 5V, obviously). You just need to measure the voltages against a good ground to see if it's the sensor or wiring.

That makes sense of the 3 wires. I was afraid energizing the clutch would be a ECM decision. Could be lots of reasons the ECM might decide to disable the A/C. I'll check the outside temperature display tomorrow. Maybe it just thinks it's cold. Maybe a scan tool will give some information. It would be strange if something decided to fail, having nothing to do with the critter that was just crawling around in it.

The temp outside can be near freezing and the AC will still turn on. It does that on defrost to dry the air, making it easier to remove fog on the inside. So you should be able to turn it on in just about any weather.

Your critter may have moved some wiring or damaged something while in there. That's not covered under the vehicle warranty but it might be covered under your comprehensive insurance. If the car was moving (not indicated) then it would qualify as a collision and (possibly) be covered under that part. Call your insurance to see where you stand if you decide to get them involved.

I only have liability insurance, with high limits, on this car but even if I had full coverage I would have a high deductible, so an insurance claim is out.
I got some information from the Alldata system at the library and it looks more complicated than it ought to be.
There's a bunch of scanner data points and functions that my Actron CP9180 scanner won't do. I need to get a better scan tool. This is not the first time it was inadequate. There is a EGR flow sensor on my truck that is supposed to be readable with a scantool. I had to pierce wires and read it with a voltmeter. That was another case of animal eaten wires, but the truck had been sitting for a few months.

I took it over to friends house who has a lift. It took 5 minutes to find that the critter ate the wire going to the compressor clutch. The damage couldn't be seen from above. Spliced in some new wire and it's fixed. I got more worried about it than I should have. The critter must have come back for revenge. I don't think he had time to chew that wire while I was chasing him with the stick.
Now I can get back to building my garage and maybe I can get my own lift.
John

I took it over to friends house who has a lift. It took 5 minutes to find that the critter ate the wire going to the compressor clutch. The damage couldn't be seen from above. Spliced in some new wire and it's fixed. I got more worried about it than I should have. The critter must have come back for revenge. I don't think he had time to chew that wire while I was chasing him with the stick.
Now I can get back to building my garage and maybe I can get my own lift.
John

Dang! Maybe they need to stop using fish oil in the rubber, eh? Glad you found it and fixed it so easily and cheaply!

So you're gonna put in a lift, huh? Hmmmm, I just might have to get your address! ;)

When I leave my car anywhere for more than a few days (airports, parks), I throw a pouch of "Fresh Cab" under the hood plus another couple inside to keep rodents away. See http://www.earth-kind.com/.