Hi all,

I have an a/c that doesn't blow cool air. Here's what I know and have done:

1. Pressure is good and there is enough refrigerant in the system. Fans work, so air is being pushed through.
2. The compressor clutch doesn't engage
3. Ran the detailed diagnostic test (turn on engine > audio off > settings > rotate volume knob ) and saw some error "2-23" in the Error History (Detailed). Ironic, as it's not very detailed or helpful. Can't find any references to "2-23" -- anyone know what this error is?
4. The Climate Control test did not return any error, but seemed to be stuck in a loop. Let it run for about 20 mins before I gave up. The magnetic clutch never engaged.
5. Checked the IPDM fuses and didn't see any that were burned
6. Seems the relays related to A/C in the IPDM are integrated so I'd have to replace the whole module if it failed. Sucks. Not sure how you tell if the A/C relay is fried.
7. Looked at the low pressure switch, but not sure how to test it. 
8. Read @Sstupid's post in the FAQ on replacing the electromagnet part of the clutch. Just posted a question on how to check voltage that specific part.
8. I've read conflicting info about the low pressure switch a) checking for continuity and b) bridging jumpers to engage. I took a multimeter to the switch and didn't see any continuity across any of the three pins. I also don't want to jump as there are reports that it may fry critical circuitry. Some say that the ECM/ECU is expecting a 0-5V signal on one of the pins and jumping wouldn't help anyways.

So that's where I'm at now. I'd like to know how to locate the problem. As I see it, we're down to three potential areas: switch, IPDM, or the magnetic clutch. Does anyone know how to troubleshoot any of those areas so I can go through the process of elimination? I bought a switch and I was going to replace it, but then realized I have to evacuate the system, so it would be a bummer if I did that and it wasn't related. The IPDM is anywhere from $50-$100 used, and of course the dealer cost of repairing the compressor clutch is somewhere in the range of $2000. Ouch.

Any tips would be much appreciated. Thanks!

I've got the same issue. I think my clutch is engaging though. Last time I checked, the tachometer would dip a little bit when I hit the AC button. This is the second summer I've let this go and I'm getting sick of sweating to death before work. Check the service manuals. Maybe there is something in there that can help.

https://www.nicoclub.com/infiniti-service-manuals

I think I'm asking too many questions. What if we narrow it to this:

I tested the pressure switch with my multimeter and did not find any continuity for any combination across the three pins. I assume it's broken because the pressure should close the circuit, right? A new uninstalled pressure switch that I just purchased does not show continuity, but that makes sense because it is not sensing any pressure. Can someone confirm/validate my thinking please?

Thanks!

Optional extra credit: anybody know why three pins? Many of the pressure switches only have two. Diagram of the pinout would be great, but I didn't find it in the service manuals.

I got around to checking out my system. I have an pressure gauge left over from when I tried to refill the refrigerant and it didn't work. The gauge says the low side is too high, somewhere around 80psi. Using my NDSII app and a Bluetooth OBD scanner, I can see the high side pressure sensor voltage value at around 0.8V, too low at around 80psi as well. Service manual is saying when the high is low and the low is high, the compressor is likely bad. Both sides are hot as well, which happens to be another symptom listed under the "high is low and low is high" table. I might try to see if I can borrow a manifold gauge from AutoZone or something to check it for sure but the evidence is pointing towards the compressor.