A/C malfunctioning

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labsy
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A/C malfunctioning

Postby labsy » Fri Jun 01, 2018 1:36 pm

Hi,

I serviced the engine during winter, changed chains, sprockets, gaskets...meaning, whole front end was teared apart. But during cold weather I did not need A/C cooling.

But now, when heat is coming, I found out, A/C does not cool. Ok, did some service:
- the refrigerator pressure switch was broken, probably during engine repair, so I replaced it with new one
- regenerated and refilled refrigerator gas

But still, A/C cooling no go.
Then I checked A/C compressor. Took off electrical connection and wired it directly to 12V+, and compressor kicked-in instantly, and vent blowing out ice-cool air. Nice, compressor is OK.

But still my auto A/C does not work.
Actually, hotter it get's outside, more hot air it blows in. Not as hot as if I turn it to full heat, but still it's hotter than outside air.

Any ideas what else could I check myself, before visiting the dealership?


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labsy
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Postby labsy » Fri Jun 22, 2018 2:03 pm

Well, I came down to possible malfunction of A/C pressure sensor in front refrigerator.

Anybody have any data on how/what to measure to test if pressure sensor is OK?

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labsy
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Postby labsy » Sun Jun 24, 2018 2:17 am

My monologue continues :)

I've tried with some AUTO TESTS as follows:
- Auto-test of lights, vipwers and A/C compressor clutch and it was SUCCESS
- Auto-test of A/C components, but could not initiate it. Test should be performed doing those steps: Ignition ON, then turn Vent dial CCV + Temp dial CV, release them and press AUTO within 3 seconds. Tried multiple times, but could not get it started.

So, what I know so far?
1.) A/C compressor is OK, it can be started by control commands
2.) Obviously some other component does not give OK signal, most probably A/C pressure switch.

I've tested +5V at A/C refrigerant pressure switch, so it's getting power supply. Would like to manually bypass its OK signal, but how?

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labsy
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Postby labsy » Tue Jul 03, 2018 12:59 pm

Finally got to proper data about A/C refrigerant pressure sensor.
It's one like this:
Image

what I did was connect 2kOhm and then 50kOhm resistor between 5V feed and return Signal wire to bypass the sensor. In one case A/C kicked in alone, and in other case A/C + refrigerator cooler fan both kicked in.
Which is OK...in one case CPU thought refrigerant pressure is within low limit, meaning it's not hot, so only compressor kicked in, while in other case CPU detected high pressure, meaning refrigerant is hot and needs cooling.

With this simple procedure I found out, that my NEW A/C pressure switch is broken and needs to be replaced.
Took me 1 month to check everything else and come back to just replaced (obviously failed) pressure switch, which needs warranty replacement.

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disallow
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Postby disallow » Fri Jul 06, 2018 12:42 pm

Friggin awesome info on the switch! I was just going through the same thing on my 2010 rogue which uses the same switch. Fortunately I had a Genuine Nissan one in my tool box, so I replaced it, and the AC works wonderfully now.

Sorry I didn't see this post sooner, could have at least chimed in!

t

minostar73
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A/C pressure switch removal

Postby minostar73 » Sun Nov 25, 2018 8:54 am

Hello,
This switch is screwed on to the dryer correct?
Do you have to discharge your refrigerant before removing the switch?
Thanks for any tip.

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disallow
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Re: A/C pressure switch removal

Postby disallow » Sun Nov 25, 2018 11:55 am

minostar73 wrote:Hello,
This switch is screwed on to the dryer correct?
Do you have to discharge your refrigerant before removing the switch?
Thanks for any tip.
Yes if you don't it will all leak out when you remove the switch and you'll freeze yours hand.

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labsy
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Postby labsy » Tue Jun 18, 2019 5:49 am

Hmm...problems again.
Anybody knows where A/C compressor relay is located? I've searched through all relays in engine bay, around IPDM box, but none of those is for A/C compressor.
Any idea where else to look?

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disallow
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Postby disallow » Tue Jun 18, 2019 12:53 pm

Pretty sure that the AC compressor on off is part of the IPDM functionality.

You can check the compressor clutch engagement by doing this test:

https://www.google.com/amp/s/www.titant ... ml%3famp=1

If you hear the AC compressor click during this IPDM self check, then the issue is not the compressor. My money is on the pressure switch or low refrigerant.

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Graham W
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Postby Graham W » Thu Jun 20, 2019 6:31 am

labsy wrote:Finally got to proper data about A/C refrigerant pressure sensor.
It's one like this:
Image

what I did was connect 2kOhm and then 50kOhm resistor between 5V feed and return Signal wire to bypass the sensor. In one case A/C kicked in alone, and in other case A/C + refrigerator cooler fan both kicked in.
Which is OK...in one case CPU thought refrigerant pressure is within low limit, meaning it's not hot, so only compressor kicked in, while in other case CPU detected high pressure, meaning refrigerant is hot and needs cooling.

With this simple procedure I found out, that my NEW A/C pressure switch is broken and needs to be replaced.
Took me 1 month to check everything else and come back to just replaced (obviously failed) pressure switch, which needs warranty replacement.
where is this sensor located?
My Motor turns but despite being refilled its the same, blows warm most of the time. No leaks detected.....

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disallow
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Postby disallow » Thu Jun 20, 2019 8:43 am

Graham W wrote:
labsy wrote: It's one like this:
Image
where is this sensor located?
My Motor turns but despite being refilled its the same, blows warm most of the time. No leaks detected.....
Not sure on your diesel, but on my 4.0L V6 it's close to the battery on the left side of the engine bay, located on the high pressure line.

Don't mistake the power steering pressure switch for this one. I did that once in case you were wondering...

t


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