# Where is located the AC fuse?



## Mehcoib (Nov 24, 2010)

Hi guys,

I bought my 07 Sentra 2.0 ~6 month ago, and today I discovered that AC was automatically turned on each time I select any of the defroster positions, even if the AC light is off, as described in owner manual! I now better understand why my MPG was so poor during cold season! 

So I want to "deactivate" the AC bu removing the corresponding fuse. But where is it located? I checked into both inside and hood fuse boxes but I didn't find anything specific to the AC.

Can anyone help me?

Thanks a lot!


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## smj999smj (Jan 1, 2006)

You can't disable the AC by simply removing a fuse without affecting other systems of the HVAC system. You could remove the AC relay, but this may cause a trouble code to set as it is controlled by the ECM (I'm not sure if it will throw a code, but it might). AC is turned on in the defrost modes to remove moisture out of the air and decrease window fogging. Nissan addressed this in the TSB below. Personally, I would leave it alone.

Classification: HA03-002A

Reference: NTB03-048A 

Date: April 7, 2006

A/C COMPRESSOR OPERATION DIFFERENT FROM EARLIER MODELS

This bulletin has been amended. The Applied Models have been updated. No other content has been changed. Please discard all previous versions of this bulletin.

APPLIED VEHICLES: 
2003 - 2006 Sentra (B15) - with manual A/C
2003 - 2004 Altima (L31) - with manual A/C
2003 - 2004 Frontier (D22) - with manual A/C
2003 - 2004 Xterra (WD22) - with manual A/C

SERVICE INFORMATION

Vehicle owners may report the A/C does not turn OFF at times.

Even though the A/C switch is OFF:

^ The A/C compressor cycles. 
^ There is slight idle speed fluctuation. 
^ The outlet air temperature is cool.


The above conditions may be normal.

There have been HVAC system improvements and design changes.

^ These changes affect the way the A/C compressor operates.

These improvements help reduce window fogging by dehumidifying the air.
For the Applied Vehicles in this bulletin:

^ When a defrost mode is selected (either "defrost" or "foot/defrost"),


and

^ the outside temperature is more than 36 - 37°F (2 - 3°C),

^ the A/C will remain ON with the Mode Control Knob in any mode position, even if the A/C button is OFF.

NOTE: The A/C indicator light will not be ON, when the system is operating as described above.


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## Mehcoib (Nov 24, 2010)

smj999smj said:


> You can't disable the AC by simply removing a fuse without affecting other systems of the HVAC system. You could remove the AC relay, but this may cause a trouble code to set as it is controlled by the ECM (I'm not sure if it will throw a code, but it might). AC is turned on in the defrost modes to remove moisture out of the air and decrease window fogging. Nissan addressed this in the TSB below. Personally, I would leave it alone.
> 
> Classification: HA03-002A
> 
> ...


thank you very much for your answer, this is very helpful.

Nevertheless I still think it is weird to have A/C on during winter!! And does it mean A/C will be on even if I set the temperature control dial on warm?? Maybe Nissan should let us deciding if the air needs to be dehumidified instead of setting it automatically (A/C on = loss of power + poorer gas milage)...

For my information, can you tell me where are located the fuse and the relay for A/C? Maybe I'll do some tests.


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## smj999smj (Jan 1, 2006)

Nissan isn't the only manufacturer that runs the AC in the defrost mode. GM's and Fords, as well as a number of manufacturers, have been doing this for years. Modern AC compressors are fairly efficient. In fact, most vehicles today will get better fuel mileage at highway speeds running the AC and having the windows up than they would with the AC off and having the windows down. The AC clutch relay is located in the relay box in the engine compartment, passenger side, between the coolant overflow bottle and the inner fender.


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## Mehcoib (Nov 24, 2010)

smj999smj said:


> most vehicles today will get better fuel mileage at highway speeds running the AC and having the windows up than they would with the AC off and having the windows down.


In Canada we usually don't open the windows when driving on highway during the winter!  So having the A/C turned on during ~5 months will definitely increase my fuel consumption. I'll do tests before deciding what is best, with or without A/C...

Anyway, you have been very helpful to me, you seems to know cars very well and I hope you'll still be here when I'll come back in a few days/weeks to explain the 2 others (little) problems I have with this car!! (2 different sounds coming from the front end)


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## smj999smj (Jan 1, 2006)

I'll be here. I worked for Nissan for 16 years and left as a Nissan Master Tech in Oct., 2003. I'll help when I can.


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## Mehcoib (Nov 24, 2010)

smj999smj said:


> The AC clutch relay is located in the relay box in the engine compartment, passenger side, between the coolant overflow bottle and the inner fender.


sorry, I don't find the relay. Here is some pictures I took this morning, can you help me?

Passenger side:









Driver side:









Open:

















Did I miss something?


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## Mehcoib (Nov 24, 2010)

I read in service manual that the AC relay is located in the IPDM E/R. But... I see the AC compressor fuse, but I can't find the AC clutch relay. The manual says none of them are removable but I can't imagine we have to change the whole IPDM module in case of a bad relay...

So does anyone have an idea about the AC clutch relay? maybe I should check them one by one.

Or would it be simpler to unplug the compressor connector?


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## smj999smj (Jan 1, 2006)

The A/C relay is internal of the IPDM and, yes, you would have to replace the IPDM if the relay went bad. So, you're best bet would be to unplug the compressor clutch, itself. You could always install a manual on/off switch on the ground side of the clutch circuit if this is something you really want to pursue.


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## Mehcoib (Nov 24, 2010)

smj999smj said:


> The A/C relay is internal of the IPDM and, yes, you would have to replace the IPDM if the relay went bad. So, you're best bet would be to unplug the compressor clutch, itself. You could always install a manual on/off switch on the ground side of the clutch circuit if this is something you really want to pursue.


Actually removing the A/C fuse (not the relay) in the IPDM has the same effect as unplugging the compressor (I checked this afternoon), so that's the solution I chose. Thanks!


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## smj999smj (Jan 1, 2006)

That's easier, yet!


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