Check system pressure first.

To the unsuspecting eye, the clutch often LOOKS like the failure, but usually there is logic built in where the clutch is disabled if system pressure is below a threshold in order to save the compressor.

 

I had one of those A/C top off canisters with a gauge laying around. Hooked it up as per instructions (engine running, A/C system on) and pressure was reading zero.

I then squeezed that trigger to fill it up a bit. Within 5 seconds it was at 30, in the "green". However, clutch didn't start cycling. In my memory, it would take longer to go from 0 to 30 than 5 seconds. Something's wrong.

Any guesses before I take it to a shop and spend $$$ on diagnostic fees?

 

As a repair shop manager and certified tech I would advise u to find a good honest shop that has a good reputation and just eat the cost to have the entire climate control system properly diagnosed by a certified tech. The system is very complex and specialized tools and proper knowledge of the system is a must. Don't just squeeze in refrigerant from those cans u don't know how much is going in or how much is already in the system and the stuff with all those leak seal additives just makes things worse and if it turns out it is an electrical problem and the refrigerant charge was ok the whole time then shoving in a bunch more refrigerant will blow the compressor and require much more repairs when it may only be electrical or simply needed a new compressor clutch. Most shops like mine have evacuation and recharge machines that properly evacuate the system and it weighs thr exact amount it pulls out so u will know what the system has in it. Those gauges on the store bought cans are not the way to determine the refrigerant charge. If u do not have the knowledge or experience to do the work u are much better off having a good shop at least do the diagnostic so u will at least know the root cause of the problem and then u can decide on repair options from there. My shop charges $100 for an HVAC diagnostic and that's about the standard cost to diagnose it right. It's not alot of money to find the exact cause if u haven't the right tools and knowledge to tackle the job. Much luck to u!

 

If the pressure was ZERO - yeah you've got something big wrong.

 

Closing the loop here: Brought it in to my favorite mechanic. It was a hose that failed in the cold Texas winter, and all coolant leaked out. But by running it, a valve also failed. So between replacement of the hose, the valve, and a full recharge I was still out $1100. But I have working AC again.

 

See I told u an honest pro would help. A/C work isn't cheap but it was done properly and it works lol. Those autozone can gauges weren't gona solve that issue I'm glad she is up and running and I live in the inland ca desert so I know the importance of working a/c lol