# 2005 Pathfinder - Please help me get my AC system back up?? Summers coming!



## scottyk (Apr 24, 2011)

Hi all. First post here! Ill try to keep this to brass tax.
I have 2005 Pathfinder XE 4x4.

1.I noticed the air stopped coming out cold.

2.I bought a can of charge to charge the system and the air came out cold for about 2 minutes, when I noticed the green coolant was spraying out of the compressor "somewhere".

3.I couldn't see where the leak was from, so I brought it to Nissan dealership, where they diagnosed it as "faulty pressure relief valve on compressor" and recommended to have the whole compressor replaced.

4.Sometime shortly after the AC light on the on/off switch stopped working and compressor would no longer turn on

5.Yesterday I went to unscrew the pressure relief valve, and realized I could have spun it off with my fingers and air escaped and bubbled a little green.

6.Completely shocked I tightened the valve and filled with another can of charge..The charge reads about 50psi (which is slightly high alert according to the can)...There appears to be no leak and it holds pressure.

7.The light is still off on the AC button and the compressor still wont turn on.

I tried to jump the plug that goes into the low pressure cutoff switch, but Im not exactly sure which wires to jump. I used a paperclip and it made the engine rev up and the check engine light came on.

Can anyone tell me how to bypass the switch and jump the compressor to cycle the coolant through or how to properly get my AC system back up? Thanks!

ps. I checked all relevant fuses


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## Kenrod (Apr 24, 2011)

I also have a 2004 Pathfinder and am trying to find the blower motor resitior switch. I was told it is behine the glove box, but I do not see it.
Does anyone know where I might look?
Help please,
Thanks,


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## ahardb0dy (Nov 9, 2003)

I'm not an AC expert I just know some things from working on my system, usually when the AC clutch doesn't engage it can mean the system is low on freon, quick test is to unplug the connector from the low pressure switch usually mounted on the accumulator/drier, there are only 2 pins in the plug. If you jump the 2 pins in the plug with a pc. of wire or paper clip and the clutch engages that you are probably low on freon. there is also a high pressure switch and as you know a relief valve usually mounted right on or near the compressor. First stop using freon that contains the green dye, a little dye is ok in the system but too much is a problem. As for the light in the switch not coming on first check all the fuses, it's possible the compressor seized up causing a fuse to blow and the light may not come on. I would download the FSM or take the truck to an AC shop. I don't have experience with the newer Nissans.


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## scottyk (Apr 24, 2011)

OK, Thanks. 
The plug that came off the low pressure cutoff switch had 3 wires going to it.
1. pink 2. orange 3. black
I believe the black is ground.
I tried all 3 jump combinations and didnt get the clutch to engage. 
I believe the reason the on/off switch light doesnt come on is because one of these wires signals to computer to shut down the whole AC system when it senses low pressure (from what I read)
Ive also read that I should get a high pressure guage for the high end side and when the system is running correctly both psi should be about the same. (low and high)

Also Im wondering is the green liquid just a dye and has nothing to do with the pressure of the system? Is it only the pressure of a gas that actually does all the refrigeration and not the liquid? I thought the green liquid was a refrigerant. ( But I have no knowledge of this system..I just want my AC back)
Thanks!


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## ahardb0dy (Nov 9, 2003)

the green is just a dye, I just grabbed this from another site:

"Components of Automotive Air Conditioning
Your air conditioning system is made up of a compressor, a condenser, an evaporator (or drier), refrigeration lines and a couple of sensors here and there.

* Compressor: This is the heart of your a/c system. The compressor is what takes the refrigerant (the gas) and pressurizes it so it will cool the air. It's run by an engine belt. The compressor also has an electrically operated clutch that turns the compressor on and off as you demand more cool air.
* Condenser: The condenser is like a miniature radiator, usually mounted at the front of the car right next to your big radiator. Sometimes the condenser will have its own electric cooling fan, too. The hot, compressed air passes through the condenser and gets lots cooler. As it cools, it becomes a liquid.
* Evaporator: The evaporator is another little radiator that does just the opposite task as the condenser. As the super-cool liquid is passed through its tubes, air is forced through and gets really cold, right before it hits your face. As it warms up again, the refrigerant starts turning back into a gas.
* Thermal Expansion Valve: You don't always want to freeze your toes off, so the a/c system has a valve that controls the flow of super-cool refrigerant to the evaporator. This way you can regulate how cold the air blowing on you gets. There are a few types of valves in use these days, but they all do the same thing.
* Drier or Accumulator: The drier, also known as the receiver-drier, is sort of the safety catch for your system. The compressor is only supposed to compress the gas form of your refrigerant. However, there's always a chance that some liquid could make it back that far. The drier catches this liquid before it can damage your compressor. Since even the tiniest leak or careless installation can introduce water moisture to the system, the drier absorbs this chemically, using what's called a dessicant (similar to that packet of "DO NOT EAT" that comes with electronics). The drier also has a filter that catches any gunk that might be in there.

That's pretty much the whole story! Different systems also have sensors here and there to tell it pressure and temperatures, but they are specific to a make and model of vehicle. "

I know from my own experience that if the expansion valve is clogged than the freon just circulates thru the system, with out it working correctly there is nothing to control the pressure and it won't cool at all.

not sure about your low pressure switch the ones on my 2 nissans (older) only have 2 wires, I suggest you go to this site, AC forum really smart guys there:

http://www.autoacforum.com/

or take it to a AC shop

as for the high and low pressures being the same I do not think that is correct, I just had my car's AC re-done by a friend who does AC and the high and low side pressures were no where near the same. Let us know how you make out.


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## scottyk (Apr 24, 2011)

OK well I actually got the ac light to turn on and work for a minute.
I got the compressor to turn by tapping the low pressure cut-off.
Unfortunately I turned it off before the freon cycled through. I think the valve is sticking/faulty..I now know its not fuse or electrical, but the sensor


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## ahardb0dy (Nov 9, 2003)

which valve do you think may be sticking? The low pressure switch is just like a sensor nothing to stick, maybe a bad electrical connection or bad low pressure switch.


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## scottyk (Apr 24, 2011)

I assumed there was a mechanical valve inside the :
low pressure cutoff switch

When I banged it hard with a screwdriver, the compressor kicked on.
This happened while the controls were set to high fan, full heat, and windshield defrost.

Also the AC light on the on/off button came on when the compressor did.

So I then turned the dial to full cold, and turned it to Max cool, with the AC light on and compressor running...

Because I need to install the blower motor resistor, number 1,2,3 on the fan setting is off.. (only 4 blows high)

While the AC was running, I turned the fan blower dial to 3 (which turns it off), and when I turned it back to 4, the AC light went off as well as compressor..

I wish I let the freon cycle through the system, but I thought the blower fan turning off wouldnt matter..

Cant get it to work again.. I think Ill just spend the $80 to buy the new switch.
Do you know if there is a shrader valve behind the LP cutoff switch or will it decompress the system? Thanks for feedback!

Also I believe the switch problem and system decompressing are related. Everything worked fine before the high pressure relief valve came loose and lost pressure. Seems unlikely the switch would go bad at the same time the HP relief valve came loose.


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## ahardb0dy (Nov 9, 2003)

not sure about removing the switch, I would download the FSM for your truck you can find them online for free.

sent you a private message


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## scottyk (Apr 24, 2011)

any idea where I could get the FSM for free?


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## scottyk (Apr 24, 2011)

Turned out the blower motor resistor was solely the problem.
The electronic failure caused the AC light not to come on, the clutch to not engage..I replaced and recharged and all is well! Thanks for your help ahardbody


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## ahardb0dy (Nov 9, 2003)

Glad you figured it out


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