Recently my A/C stopped working.
I expected it to be low, so i started with a refill, but that did not solve te problem.
There was/is no leak, A/C should have worked before the filling, but at least it has new oil and R134 now.

The compressor is not running, so the shop expected the compressor to be the problem.
I am not sure about it, i checked the blue wire that feeds the magnetic clutch, but this is not getting 12v on the B connector in this image.

After that i checked the fuse in the IPDM, accoarding to the manual it is fuse 49, and the wire that goes to the magnetic clutch is wire 48.
The fuse is ok, and the wire from IPDM to magnetic clutch is ok, so i do not understand why i am not getting 12v on the magnetic clutch?



I tried to rotate the compressor manually, an that is possible, i do not feel any heavy spots during rotation.
I also tried to activate the magnetic clutch by giving it 12v direct from the battery, but the clutch did not work that way either.

When i start the car everything works normally, no errors, except from hot air.
The radiator fans turn on, and when A/C is turned on or of, it is shown on the display, also rpm, changes at that moment.

Is there a way to test or override the Refrigerant Pressure Sensor?

I am a bit lost now, have no idea what the problem is
I do not really like the dealers around here, hope someone here knows what's broken.

 

Yes you can test the pressure switch for function, it's located behind the grille on the right/passenger side. Unplug the switch and put a paperclip in the harness to jumper it, if the compressor turns on while the switch is bypassed AND YOU ARE 100% SURE THE PRESSURE IS CORRECT BY READING IT WITH A MANIFOLD then replace the switch. EDIT: Forgot Nissan uses a different style of switch, later post talks about how to backprobe the ECM to test for voltage from the pressure switch.

To replace you just unscrew it, a tiny bit of refrigerant will be lost, the switch is basically pushing down on a schrader valve so it will self-seal once you have unscrewed it enough, just be quick about it once it starts hissing, you're committed at that point so just keep unscrewing quickly. Same with installation.

However there are quite a few components that can fail on the system and it's usually a LOT quicker to just take it to the dealership for a 1 hour diagnostic, they can read all the ambient sensors, the state of everything, and quickly give you a diagnosis.

Have you tested for 12v at the compressor clutch harness to verify it's not just a burned up clutch magnet? Nevermind, you did.

Section HAC - Heating and Air Conditioning has steps to put the AC amp into diagnostic mode, one of the test modes will cycle the compressor on/off. I would do the self-diagnostic and see if the compressor DOES cycle on, this will rule out that it can function but is being blocked by some other sensor.

There is a relay in the IPDM that the fuse 49 supplies power to that may have failed, it's one of the internal relays that is "not serviceable" although you could desolder it and put a new one in. Most folks opt to replace the entire IPDM when a relay fails. However you need to verify that the signal is actually being sent to close that relay and thus the self-diagnostic test or a dealership 1 hour diagnostic.

You say you applied 12v power to the clutch magnet and it didn't close the clutch? It should snap the clutch shut it's just an electromagnet that pulls the front metal part of the clutch up onto the AC pulley. You can test the clutch with your hand and push on it to make sure it moves, there should be a very small gap between it and the pulley and you can easily push the gap closed with your hand. If it won't move then something might be jammed up on the clutch but I've never seen one fail like that ever. Normally the friction disc just wears out and it won't grab anymore or the electromagnet fails and won't pull it in.

However you said you're not getting 12v on the harness to the clutch so I suspect it's some other problem, just odd that you putting voltage directly to it didn't snap it shut.

 

I tried to acces the pressure switch, but the upper radiator cover seems to be stuck somehow, already made a small tear on it.
This is a EX35, But the cover is the same, they make it look so easy, but i am afraid to break the front bumper or cover.

I saw the pressure switch has 3 pins, wich pins do i have to connect?

I have not tried to power the clutch magnet with running engine, because MAF and air filter were removed while testing.
Is it possible the clutch is that silent you wont hear anything? I expected some clicking sound.

About the local Infiniti dealers, we only have 2 dealers here, Amsterdam, and Rotterdam.
They charge about $150 per hour, so i am trying it myself first.
Maybe a Nissan dealer can do it as well, if they have the right equipement/licenses.

I can try the diagnostic mode, maybe that will tell me more, i have the service manual.

 

You can test the clutch with the car off, it's just an electromagnet you're turning on the pulls the steel housing of the clutch disc onto the pulley, the big electromag is behind the pulley.

Or you can unplug the harness, poke your meter test lead into the harness then put everything back together with the lead coming up around the intake/maf.

Forgot you're not going to be able to jumper that pressure switch since Nissans all use a combined high and low pressure switch all in one and that data is sent to the ECM for idle control. You can test that it's working though by backprobing pin 105 on the ECM harness, with the engine running and the AC switch ON it should be reading 1 to 4 volts.

Here's the ECM harness so you can find pin 105, looks like it's a blue wire.

 

Now i am lost, first you told me i could bypass the pressure switch, now you say i can't


Visited the Nissan dealer today, they can't check what's the problem, so i need to visit the Infiniti dealer if i can't find it myself.

 

I tried to do the seld-diagnostics, this is all i get
Accoarding to the manual, at code 41 and 42 the A/C compressor should be running, but it is not.
If i have any errors or fault codes, where should they be visible?

 

I gave you some bad advice about being able to jumper the pressure switch, you CANNOT jumper it. You can check it's voltage though by backprobing the ECM harness with the engine running and the AC turned on, that will verify it's working.

Hook up a digital multimeter probe into that B connector on the compressor, then put the intake back together so you can run the car. The other probe on the multimeter needs to go to ground, you can just hold it on the timing chain cover or something.

Now start the car and get back into the 40 series codes. Turn it to 41, 42, 45, or 46 and see if you get 12v on that B connector. Then turn it to 43 or 44 and it should have zero volts.

 

Also on the self test, the first test will display a number 2 on the screen, wait a minute until it turns into a 20. This verifies that the AC is actually reading data from every sensor.

Then rotate the temp **** clockwise to 3, wait a minute until it turns into a 30, that verifies everything is hooked up on the blend control/motor control side.

 

Today i tried the self diagnose again.

I added a wire to the B connector (44) and run the test again.




Today the results are differend from last time, the IPDM seems to work ok today, I have power to the magnetic clutch today, but the clutch is still not working.

The video shows the whole test, 2 turns 20, 3 turns 30
After that i tried 41 to 46, and all seems to work
What does test 51 do?
After this i ended self diagnose mode, and also at that moment i have power to the magnetic clutch.

I have no idea what went wrong in previous tests, but i am happy with this result, it looks like i only need a new magnetic clutch, but the IPDM is okay.


Now the next point, how to remove the magnetic clutch from the car?
The space is very limited, i think i will have to remove the coolant reservoir, and maybe the electronic fans from the radiator, just to have some room to work.
I think there will be threadlocker on the centre bolt, so i need some room to get it off.

Should the clutch magnet be the same on HR 350Z or 370Z?
These parts are a lot easier to find around here

 

Ok since you are getting power to the magnetic clutch I would remove the accessory belt from the compressor and see if you can spin the pulley by hand WHILE IT HAS POWER. Spin it by hand with the car off so you can see how easily it spins with the clutch turned off, then turn the clutch on and it should be significantly more difficult to turn. If it's NOT more difficult to turn there are two components that may have failed.

Firstly is the friction disc part of the clutch which is on the outer edge of the pulley, the clutch friction material can wear very thin OR have worn down a little and need adjustment. I'm not 100% sure on the spec for the clutch gap on this car but most vehicles it's usually like 0.020 inches or 0.5mm you use a feeler gauge to check the gap, and make sure to check in a couple places around the clutch.

The second item that can fail is the electromagnet itself, this is BEHIND the pulley. You should be able to use a digital multimeter and read the resistance of the harness on the compressor and it should NOT be 0 or 1 ohm (open circuit).

EDIT: the gap spec is correct, here's a couple snippets from the FSM. The part they're referring to as "coil" is the electromagnet.