Does the ac compressor have a shut off valve or whatever to stop it from constantly running with the ac button on when the system has no refrigerant in it? My ac refrigerant pipe was snapped in half (somehow?) so the car has no refrigerant in it but the ac button has been on quite a lot, would this have caused any damage to the compressor or does it stop it from working? also if it doesn't, is there any visible way of telling if the compressor is working? there's definitely a change in engine noise when clicking the button but not sure if that means anything related to if the actual compressor is working or not.. 

There is a low pressure switch in the system.  As soon as the pressure drops below the threshold, the switch cuts power to the AC compressor.

The dash light will still come on.  The engine ECU may still run the 'AC' engine map, upping the revs a bit during idle.

You can check the electrical side of the compressor still engages by bridging out the low pressure switch, however I wouldn't suggest trying it on a known dry system as that could cause more damage.  There is no way to visually check if the compressor would still function correctly. 

On 11/3/2022 at 9:54 AM, TomsFocus said:

There is a low pressure switch in the system.  As soon as the pressure drops below the threshold, the switch cuts power to the AC compressor.

The dash light will still come on.  The engine ECU may still run the 'AC' engine map, upping the revs a bit during idle.

You can check the electrical side of the compressor still engages by bridging out the low pressure switch, however I wouldn't suggest trying it on a known dry system as that could cause more damage.  There is no way to visually check if the compressor would still function correctly. 

Thanks for this, I got my ac regas done today and since realised that the revs weren't actually going up with the ac button without the gas in it, it now puts the revs up noticeably, I hear the click from the compressor, see the compressor plate spinning, the ac fan spinning and the ac is ice cold 😁

I've noticed that when my ac kicks in it seems to make a weird noise (seems as if it's more inside the car rather than coming from outside) anyone else have this noise or have any idea what it could be? is it something thats worrying or dangerous etc or? (see attached video, ac turned on at about 3/4 seconds when the noise starts coming, if you guys need a better video I can try my best) https://youtube.com/shorts/gmXd97K-OJ0?feature=share

A bit of hiss or gurgle is acceptable, your kitchen fridge probably makes the same noise.

But it could be a sign of gas levels dropping.  Just keep an eye on it over the next week or two.

If you're worried about AC gas in the cabin, you'd smell it, it's really distinctive and chemically.

2 hours ago, TomsFocus said:

If you're worried about AC gas in the cabin, you'd smell it,

shortly before you pass out and loose consciousness 😧

 

 

Only kidding !! It will not affect you a part from the smell.