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Discussion Starter #1
Hi to all,

Since two days, I've expierienced a problem with AC in my MO.
At the beginning, it was like when I was staying in the traffic jam, or just stayying, even the AC was turned on, there was no cold air commingg out. The rpm's was in normal (around 750rpm, it is the first bar before 1000rpm).

Then, when I was driving fast, the AC was working, cold air was comming out.

At the end, yesterday on the highway, I was going around 180-200kmh (110-120mph), and the AC was not working at all.

I went to Nissan dealer, immieadetly, to check the problem.
What they found was:

1. No cold air comming out,
2. Fan is turning on, when AC is turned on,
3. Compressor is not turning on (usualy you can hear this when it is turning on),
4. No faults in the computer unit,
5. Pressure by H and L in AC unit was 8 bar (116 PSI, 800kPa)

And now is the problem: we couldnt find out, what is the correct pressure in the unit. There is no information on the label in MO, no information in the manual, and I also couldn't find it out in internet.

The only thing they found was in their documentation for european MO (2005) that the H pressure should be between 1 something and 24 something bar (my MO is US version 2003) so they didn't wanted to play with this without detail information, not to break the system.

After some search (it was already late, so they want to close service) we agreed to check on that later. So I drove back withou working AC.

And now the surprice: when I went on highway again, and start do drive fast (over 4000rpm, 110mph), the AC did turned on again, and start working.

Now the questions:

1. Anybody did have the same problem?
2. What is the correct pressure in the AC system in 2003 MO US version (SE AWD).

I'm confused. As maybe some one from you know, in about 1 Month I've changed the alternator (recall issue), and also computer for AWD unit, with the AWD swith (don't think this is somehow connected).
It does not seems to be broken ... maybe some cabel or conector, because of the heat is circuting and the compressor is not turning on.

In US there was no problem with AC, it was working fine, even the temperatures was much more higher than in EU (Alabama), but I never was driving so fast in US ;) like I'm driving here :)

Any advise or information will be appreciated.

Thanks

Mateusz
 

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matik-

I can't say I ever had that problem because I have never been able to just cruise around at 120 MPH!!!

There was a problem similar to yours posted recently by elliotgb. Apparently when the dealer changed the alternator he failed to reconnect the electrical harness to the A/C compressor. However, in you case I am assuming the technicians working on your car would have noticed if the harness was not corrected. But just to be sure, I would have them check it. A picture of the harness connector and compressor are posted below.

Good luck.

-njjoe
 

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matik-

The following chart is from the 2005 Murano (US) Service Manual.

-njjoe
 

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Discussion Starter #4
njjoe!

Thank You very much for fast and detailed information!

I will let them check the connection of alternator (althought, I think they did that propery, otherwise proably there will be no charging (??) ).

According to the chart, I'm also not so ensured, does the pressure is correct at my car.
Lets say that the usual temperatures are around 25 celcuius degrees, so it will say, that the H (high) pressure is in normal (around 8 PSI) but what I can not understand, and it is pretty surprising for me, why the L (low) pressure, is at the same value (which should be acctualy around 2-3PSI).

I will contact tomorrow with the service, and let them check on the issues You posted.

You see ... the problem is, the MO's in Poland are not so popular. I'm still lucky, that these guys by my service, did performed some services on MO's from US, but still, sometimes it can be, they need to learn something ... maybe :)

Thank You once again, if somebody has some idees more, they will be mostly appreciated.

Best regards - Matik
 

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matik said:
According to the chart, I'm also not so ensured, does the pressure is correct at my car.
Lets say that the usual temperatures are around 25 celcuius degrees, so it will say, that the H (high) pressure is in normal (around 8 PSI) but what I can not understand, and it is pretty surprising for me, why the L (low) pressure, is at the same value (which should be acctualy around 2-3PSI).
Matik-

According to the chart, at 25 degrees Celsius the HIGH pressure side should read between 116.0 and 142.8 psi., and the LOW side should read between 28.7 and 35.5 psi.

Here are links to two related threads concerning a problem that appears very similar to yours: http://www.nissanmurano.org/forums/showthread.php?s=&threadid=6838
http://www.nissanmurano.org/forums/showthread.php?s=&threadid=6774

I hope this helps.

-njjoe
 

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Discussion Starter #7
njjoe,

So sorry for my stupidyty :) I ment kPa's of course ... not PSI.

Thank you all very much, I hope this can help to solve the problem by a dealer.

Best regards

Matik
 

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as intermittant as it is, I will say it is an electrical connection.

It could be on the compressor or on the low pressure cutout switch which is usually located on a canister looking thing.

I had a GM truck (dually crew cab) that decided to have AC problems on the way back from a Florida vacation. As the truck was a deep laguna blue--it got very toasty very quickly in 100+ temps.

At a rest stop I got out and raised the hood and pulled the plug off the low pressure switch and jumped the sucker out. By golly we had dam cold air allll the way back to Atlanta. I left the sucker jumped till I sold it two years later--so it definetly was defective and not low on freon.

But, in your case I say it is a connection--unless they opened your AC system, in which case it would be low freon.

Good luck!
 

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Discussion Starter #9
One more thing ....

I still can not understand ... if it will be a electrical connection by a wire plug, it supose not to work at all!
And the very funny situation is, when I'm driving fast (over like 1000-2000 rpm) the AC is working.... but just once in this case on highway, it was not working ... today was more or less ok.

If it will be, that the plug is not plugged in: it will not work at all (right?).
I was thinkig maybe because of high speed and higher temperatures (in engine room), this disconnect from time to time (because of temperature condition), but still: as much as it is warm, it should get better connection, and worster by lower temperatures (metal is shrinkig by lower temepratures) ...

Anyway ... I think I will just talk to them yesterday, put together all your information, and let them check it ...

Matik
 

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Is it possible that at those speeds (110-120mph) the accessory belt is turning so fast, that it is slipping from the compressor pulley? In such a case, the compressor would not turn and you would get no AC. The belt might have to be tightened (by adjusting the tensioner) or simply replaced.

Also remember that the ECU automatically disengages the AC for maximum power at WOT. Every car does this from what I know.
 

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"Also remember that the ECU automatically disengages the AC for maximum power at WOT. Every car does this from what I know."

I think you are right.

I still remember "back in the olden days' installing a Vacuum operated switch to open the compressor ckt when vacuum dropped very low (WOT).

Matic, electrical connections by plugs are notorious for being intermittent.
I'm not taking a dog in this fight, but an intermittent connection is certainly a possibility.

Homer
 

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Discussion Starter #12
updated ==> solved

Hi to all!

First, one more time big thanks to You all for help.
This was very accurate!

Today, I was so nervous because not working AC, that I've tried to take the things in my own hands.
Thanks to your information and posted schemes, I located the disrubtion very easy.
The problem was plug which is connected to a compressor.

It was not tight enought (it was plugged, but there is a small rubber protection on the cabel), and probably, by driving in bad terrain, it just moved out a little.

I've disconected a plug (to get better position for that, the best way is to remove protection shields: one below a bumper, and one behind the front-passanger wheel), which was not so easy anyway (if you have problems disconecting it, the best way is to use a small screwdriver - like for pc's for example; staying in front of the car, you need to push it carefully in to a small whole on the right side of the plug, and then carefully push a screwdriver right, additionaly pulling carefully the plug out).
Just coreccted it, and made it much more tight, and the pushed back again.
AC working without any problems! As far ...

My concern is, however, why NISSAN made the connection cable (cord) so short!
It is almost touching alternator! And alternator can get hot (belive me! Was injured during this process ;) )
Anyway, thecord is hanging not likely in the air ... I do not like it.

So ... thanks again for any help!!!

Very very gratefull and happy - Matik
 

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Great! Glad you got it working again.

I've had to clip cable ties more than once on Mo because someone went ape on neatness instead of functionality.

If you can not cut some cable ties to get more slack for rewiring to keep the wire away from heat, consider some high temp slit plastic tubing.



Example
 

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Hi
I was s oglad to see your problem with the air con - I have recently had a similar problem but of course when I took it to the dealer,the air seemed to work fine!Hope this solves the problem since it too hot to drive withour air!
 
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