The air conditioning is blowing just air. Not hot but not cold.
I don't think the AC compressor is engaging. But I don't know how to tell for sure.
The belt is spinning the AC compressor but I don't know how to tell if the compressor clutch is actually engaged (the "knobs" are not spinning).
There is a plug with two wires which is mounted on the compressor.
Can I jump 12V to one of those two wires to see if the clutch engages? Will it hurt the ECU?
You CAN disconnect the wire to the clutch and "hot wire" it to 12 volts to see if the clutch engages. If it doesm your system is almost definitely low on refrigerant and needs to be tested and re-filled. There are high anf low pressuere shutoffs that prevent the clutch from engaging with too little refrigerant to prevent compressor damage. A compressor is like a 2 stroke engine - the oil is carried by the "working fluid" - and if that fluid (refrigerant) is low the compressor does not get properly lubricated and fails spectacularly and in an expensive manner.
A better way is to see if power is present at the clutch using a test light.(or volt meter) If thewre is power the system is calling for cooling and the clutch is not responding.
Those "knobs" on the end of the pulley apparatus spin when the clutch is engaged. Watch it and listen while someone cycles the AC on and off. You should here a click and it should start spinning. You can also check for
12V on the wire to the clutch/compressor, that's easier than putting 12V on it.Only if you put the 12V on the wires while they are still connected or put 12V on the wrong end when you disconnect it at a plug. I had exactly that happen when I took a Pontiac to a place that does car AC repair. Took them two days to diagnose that the dashboard switch was bad. When I picked it up, the check engine light was on. I probably should have gone right back, but I figured they would just deny it. I had a list of codes and the code was for something like coolant temp sensor fault or something like that. I traced it down to the engine computer. I opened the module up and found that a piece of the ground trace had been blown right off. The morons had obviously been probing around and tried jumpering 12V to some ground wire or similar going back to the computer. A piece of wire, some solder and it was fixed. I got lucky, very lucky.
On Fri, 02 Jul 2021 15:25:40 -0400, Clare Snyder posted for all of us to digest...
Good info. Also look at the clutch when it is engaged to see if it's spinning. A compressor is a lot of load and if the clutch is dodgy it may not fully engage. A non recommended way to check it is to jam a firmly held long screwdriver against the the clutch to see if it works.
Sometimes you can just get a clutch but usually you have to get the whole unit. The work involved just replacing the clutch is usually not worth it in the long run because there is no room to work.
What kind of car is this?
If the compressor & clutch are working check the blend doors motors are working.
Post back with progress.
These kind of problems are invariabley caused by leftists. The Left is a disease that must be eradicated. The only way this will end is to round leftists up and exterminate them. Otherwise they will never leave the rest of us alone to live our lives. When you have cancer you need to excise it one way or another.
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