1G A/C stopped blowing cold air, basic diagnostic checklist?

[XC92]

Not looking for anything extensive, just the basics. What do I check and in what order? I can figure out the rest. If you can point me to a link that covers this, all the better.

It worked for around 30 years then suddenly stopped blowing cold air. I've done a lot of work on the car so maybe I dislodged or broke something in the process. And yes, A/C belt is there, replaced several years ago.

 

[dwb]

Check your fuses first. Then check for refrigerant pressure with a gauge. In a pinch you could depress one of the schrader valves quickly and see if anything sprays out (wear eye protection and gloves). If little to nothing pressure-wise, you have a leak. Follow your lines around and look for oily residue, often around the fittings. That will be a sign of a leak. Check your condenser and dryer too for oily spots.

If refrigerant checks out good, move on to the compressor. You should be able to hear the compressor clutch "click" when it turns on (have a helper push the AC button while you listen under the hood). Maybe you will even notice load on the engine, or at least idle-up. My 1g still clicks and idles up even if the refrigerant is low/empty.

If it doesn't click, manually apply a +12v source to the single electrical pin on the compressor and see if it clicks and starts running (don't run it long like this since you have no fail-safe). If it turns on, you have an electrical problem. If nothing, you have a compressor/clutch problem (again, refrigerant pressure must be verified first).

 

[XC92]

Check your fuses first. Then check for refrigerant pressure with a gauge. In a pinch you could depress one of the schrader valves quickly and see if anything sprays out (wear eye protection and gloves). If little to nothing pressure-wise, you have a leak. Follow your lines around and look for oily residue, often around the fittings. That will be a sign of a leak. Check your condenser and dryer too for oily spots.

If refrigerant checks out good, move on to the compressor. You should be able to hear the compressor clutch "click" when it turns on (have a helper push the AC button while you listen under the hood). Maybe you will even notice load on the engine, or at least idle-up. My 1g still clicks and idles up even if the refrigerant is low/empty.

If it doesn't click, manually apply a +12v source to the single electrical pin on the compressor and see if it clicks and starts running (don't run it long like this since you have no fail-safe). If it turns on, you have an electrical problem. If nothing, you have a compressor/clutch problem (again, refrigerant pressure must be verified first).

Thanks, this will get me started in figuring this out. Been hot as hell here so the A/C is definitely missed.