# AC problems 2011 sentra



## ckirby (May 27, 2008)

AC stopped working in my 2011 Nissan sentra. Neighbor is a heating and air guy so he helped me trouble shoot it. All the fusses were good and it seems no power is getting back to the compressor. He is certain that its an electrical issue. He thinks it might be in the control panel inside the car. We took it out because he did goggle search and saw were some people had lose cables that when reattached fixed the problem. No such luck for us because everything plugged in firmly and was not loose. That is were I am today considering buying the control panel at a junk yard. Thought I would try a post before I went shopping. Any help is appreciated.


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## rogoman (Dec 16, 2004)

Check the A/C relay that should be located in the engine compartment on the driver's side next to the fender well.


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## ckirby (May 27, 2008)

We opened up two black boxes on the drivers side and only found fuses. I have no idea what the relay looks like. Anyone got a diagram or picture? Thanks!


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## ckirby (May 27, 2008)

Does anyone know if the relay that is on the drivers side in the engine compartment is inside the two black boxes or is it else where?


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## ckirby (May 27, 2008)

There is no ac relay in this car. The only thing that could be keeping the ac from working is a high or low pressure switch and i cant find either-one. Any help?


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## ckirby (May 27, 2008)

I found the ac pressure switch its on the back side of the radiator were the free on goes. When I disconnected the plug and plugged it back up fans came on and I could here clicking in the fuse box under the hood and the engine rpm increased. I called Nissan and they said they do have a relay for the air-conditioning however I can not find it labeled in the either black box. At this point I have two questions. My first question is does the relay control the compressor only and does the fact that fans turn on after I reconnect the pressure switch mean that the switch is ok? So far I have had one person post to this tread surly there has to be more people that are informed on this matter on this forum.


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## ckirby (May 27, 2008)

Tested the power to the ac pressure switch and it seems to be getting 5 volts to the out side prong. There are three holes in the plug two are on the out side on in the middle. I guess its pretty simple when you say three holes how they are aligned. The outside is reading 5 volts. Does anyone know how many volts go to the pressure switch again I was only able to read 5 volts. At this point I have checked all the fusses, replaced the relay fuse, and checked the voltage at the compressor and pressure switch. With no voltage at the compressor and 5 volts at the pressure switch. This was a pretty good forum a few years back but I have just really gotten no help this time around.


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## ckirby (May 27, 2008)

Can someone tell me if there is a better forum than this because I seem to wasting my time here.


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## Outkast (Jan 29, 2006)

Take it to a certified A/C shop or your local dealer. Some problems can't be diaged over the net.


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## ckirby (May 27, 2008)

No but a Nissan mechanic should be able to tell how many volts are going to the ac pressure switch and your a Nissan master tech I would think you might know that information. I don't have the money right know because I am a full time student . This is my wife's car and the only way I can get it fixed is myself. I am lucky enough to have a heating an air guy that can help take the Freon out of the lines if we need to work on it but I have to find the problem first and its seems to be electrical. He has been able to help me a lot with the issue but does not know enough about the electrical parts in the car. Its something electrical or electronic but we cant figure it out. I appreciate your reply but why your knocking down the big bucks at the Nissan dealer I am just trying to make it through the summer with an angry wife a tuition bill and a two your old. Class starts in one week and a micro biology book is 240 dollars and I don't have that I don't get the class done I am locked out of my program of study. I really think that allot of the people on here that know the answers don't wont to give them out because they work for the ask a Nissan mechanic thing are they are afraid people wont come to the dealership. If I cant fix this it will not get fixed.


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## rogoman (Dec 16, 2004)

ckirby said:


> Tested the power to the ac pressure switch and it seems to be getting 5 volts to the out side prong. There are three holes in the plug two are on the out side on in the middle. I guess its pretty simple when you say three holes how they are aligned. The outside is reading 5 volts. Does anyone know how many volts go to the pressure switch again I was only able to read 5 volts. At this point I have checked all the fusses, replaced the relay fuse, and checked the voltage at the compressor and pressure switch. With no voltage at the compressor and 5 volts at the pressure switch. This was a pretty good forum a few years back but I have just really gotten no help this time around.


Here's a section from the FSM that deals with the pressure sensor:

TROUBLE DIAGNOSIS

ECM TERMINALS AND REFERENCE VALUE MEASURED BETWEEN EACH TERMINAL AND GROUND

TERMINAL ---- WIRE COLOR ---- ITEM ---- CONDITION ---- DATA (DC)
----------------------------------------------------------------------------
- 58 B ECM GROUND IDLE SPEED (ENGINE RUNNING) 1V OR LESS
- 74 R/L REFRIGERANT PRESSURE SENSOR BOTH A/C SWITCH AND BLOWER SWITCH "ON" (ENGINE 
RUNNING, WARM-UP CONDITION,
COMPRESSOR OPERATING) 0.36 - 3.88V
- 111 R SENSOR POWER SUPPLY IGNITION SWITCH "ON" APPROX. 5.0V


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## ckirby (May 27, 2008)

Thank you I am not going to pretend that I understand all that technical stuff but I have saved it to a word document and will see if my neighbor can help with it latter. I appreciate any help I can get and I am hopeful that some how I can get this fixed so my wife does not have to go to work all summer without air-conditioning. I have never had a car have this kind of problem before. Usually its something like a fuse, relay, or simple adding Freon. According to my neighbor the Freon pressure is good so he thinks its the pressure switch, ac clutch or a bad circuit-board(something he found on goggle about the circuit-board). All the fuses have been checked one relay replaced so these numbers may be able to help isolate the problem to one or two things I hope.


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## rogoman (Dec 16, 2004)

Here's another diagram from the FSM that relates to my previous posted info:


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## ckirby (May 27, 2008)

That is a great diagram I really appreciate it. I was unable to look at the car yesterday because we had rain. We went to get gas in it could hardly see out of the windows the defroster is about completely useless with out the ac working. Hopefully I can get together with my neighbor this weekend and some of these diagrams will help us get some where. Copied the diagram and saved it one thing I am noticing is I have never seen that ac/relay marked 23.


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## Mijclarke (Jul 31, 2014)

*AC problem in my 2012 Nissan Quest*

I'm sorry you haven't gotten much feedback. I purchased a 2012 Nissan Quest a month ago from a private seller and the AC for the front seats isn't working (the rear seat AC is working). Did you ever find a solution to your problem?

Thanks,

Mike


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## Capitolman (Feb 23, 2015)

*2011 Nissan Frontier A/C Compressor Issue*

I have a 2011 Frontier 4 cylinder, manual transmission with 95k miles on it that just started having an a/c issue. The compressor cycles on and off with or without the a/c light switch on. The cabin filter is clean and the a/c is cold. Looked online last night and saw several repairs of the Thermal Control Amp part# 27675-9Z000. Any ideas?


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## smj999smj (Jan 1, 2006)

Do you have the heater control set to defrost? If so, that will run the A/C compressor.


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## Capitolman (Feb 23, 2015)

Did not have selector on the defrost. I noticed it while on a 150 mile trip with the selector mode switch on vent or the next selection past Max a/c. The outside temperature was cool so no need for a/c. The compressor was definitely cycling and the air was cold, also during this issue the a/c indicator light was not lit.


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## smj999smj (Jan 1, 2006)

I can't see this being a thermal amp (also called a "thermistor") issue. The thermal amp is used to detect the temperature of the evaporator core and to prevent it from freezing up. When it reaches a specific temperature, it cuts power to the A/C compressor clutch. There are two common problems with the thermal amp. It can go bad and the A/C compressor clutch will not come on, or, if improperly located in the evaporator core, can lead to the evaporator core freezing up and severely restricting the airflow through it.


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## cristinaharn (Mar 29, 2015)

That is were I am today considering buying the control panel at a junk yard. Thought I would try a post before I went shopping. Any help is appreciated.


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## chipahoy (Jul 1, 2015)

ckirby said:


> There is no ac relay in this car. The only thing that could be keeping the ac from working is a high or low pressure switch and i cant find either-one. Any help?


The car does have an A/C Relay. its part of the IMPD (Intelligent Power Management Distribution) Panel and is not singularly interchangeable. you have to replace the entire panel.


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## Allen Watson (Feb 17, 2016)

There must be problem in the relay, if you can't replace it by your own . Go to the dealer or ac repair technician , they will frequently replace it with the new one.


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## RickWilliams (Jun 23, 2016)

What ended up being the problem? Mine is doing the same thing. I did an internet search and this forum came up.
Thanks.


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## erick0076 (Dec 18, 2017)

wheres the diagram?


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