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Discussion Starter #1
Ok, so the A/C will not engage the clutch under normal operations. I had the system cleared and recharged over the weekend. They performed a vacuum test as part of the change and didn’t report any leaks.

Then running the diagnostics and the only code was 12. I can’t find it anyplace.

It is killing me that I can’t narrow down the problem.

Here is a picture of the code.

Lastly, the clutch engages when I run the self test using the door button.
 

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How do you get to that System Diagnostic mode?
 

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Discussion Starter #3
While the motor is running and you are in park, press settings, then hold settings and rotate the volume knob.

There are several checks that can be ran from this menu. The one you see is for the climate controls.

*the radio has to be turned off.
 

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Discussion Starter #5
The magnetic clutch on the compressor will not engage when I turn on the AC.

It does engage if I run the self test.
 

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A pocket scanner, like those used by your local auto parts store will not be able to read the BCM, nor diagnose the A/C issue you’re dealing with. A reputable shop with a full range diagnostic tool, with a very competent mechanic would be an option outside of a Nissan service dept.
 

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Discussion Starter #10
Thanks guys, I want really doing my best to show string this thing together.

Do you guys recommend one that is less than about $200?
 

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My late father-in-law was the chief HVAC engineer at UMDNJ and I tried to soak in everything he taught me about the world of HVAC. I'll do my best to help you out and try to remember things as I go.
Since you had the system evacuated and recharged, look over at the A/C clutch again. Did you actually see it engage, as in moving towards the compressor during the self-diagnostic procedure? If the A/C clutch doesn't move and just clicks, then the clutch itself is worn out. Replace the A/C compressor. If the clutch does move, this is where it can get complicated. First, disconnect the A/C clutch pigtail from the harness. Run a wire directly from the A/C clutch pigtail to either the (+) terminal on the battery or to an external 12V source. Don't connect the jumper wire just yet. Make sure to route the wire away from the fan for obvious reasons. Start the truck up and now connect the jumper wire to the +12V source. If the A/C clutch and compressor kicks on, then the problem(s) can be from low refrigerant pressure or even bad pressure sensor switches.
 

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Discussion Starter #12
Awesome! I’ll loop back. I will not be able to do this until tomorrow, but I’ll let you know how it goes.
Thank you!!

Ok team, I was able to get the air box out and eventually removed the plug from the compressor.

I ran a wire to the clutch and it did engage.

I started the motor and it was not engaged, then I placed the hot wire in the battery. The clutch engaged and started to spin.

Per Primov8 this means it is working well.

Now, is there a good way to test which sensor could be holding me out?
 

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seems you are handy with mechanics. you should download the factory service manual and read up on the HVAC section. there are more troubleshooting steps you can take. thats the same manual the dealer would use.
 

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Discussion Starter #14
The manual really just refers to using the software I don’t have. It kills me that I can’t just figure this out.
 

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then it may be time to take it in and let the dealer smoke it over. there could be some electrical fault in the wiring that it just not showing its ugly head for you to see it. also possible it could be some internal issue with the compressor. i know you can get it to engage manually..

perhaps you are low on refrigerant? have you had the pressures checked?
 

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Since you were able to trigger the A/C clutch via direct +12V, next thing to check, is the pressure sensor/switch. If I'm not mistaken, I remember seeing it near the condenser, passenger side when I was installing the radiator bypass-external ATF cooler years ago on the 04.
From what I've learned and know about the pressure sensor, it is there to prevent the A/C system from operating if the psi rises or drops below specs. Unfortunately, I don't have the specific #s but I'm sure a service manual would. Also, when changing the pressure sensor, the system must be evacuated.

I'll echo what marctronixx has asked about your truck possibly being low on refrigerant. A faulty pressure sensor could be the cause as well but to determine that, a full range scan tool is needed so it can read if the psi is below or above Nissan's specs.
 
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