Aircon compressor doesnt shut off

[marv25]

Nissan Serena 2002 QRV.R Ltd. A/T (not converted, bought from Nissan Cebu Inc.)

Hello.

Our Serena's Aircon is using a digital climate control system. But ever since we bought this car (about a year ago, second hand), I noticed that the aircon's compressor does not shut off. It always stays on even if the temperature is always set to 28-30C (the temperature range is from 18-32C).

The hotter the temperature is, the blower just turns down, but the compressor never stops working, even though it is set at 31 or 32 (heater, hot air na ang lumalabas). The only time it turns off is when I turn it off by pressing the OFF button, or when i press ECON, but it does not turn on again until i press AUTO, so the air will start getting warmer.

The disadvantages? It's noisy. And it's definetly making the FC higher.
Nissans are known for their powerful aircons because of the big compressors which is of course putting weight on the engine, and it also eats up fuel.

I tried turning off the aircon or putting to ECONomy mode, the engine feels significantly stronger and lighter. I really think the aircon is hitting the fuel consumption really bad.

Our other cars' compressors turn off once it's cold enough.

Is this normal? or is there something wrong?

Theres an AMB button on the aircon and it shows normal temperatures. even if the AMB temperature is cooler than the setting, the compressor still turns on.

Thanks for reading.

[1D4LV]

the thermostat?

[bambino]

cars nowadays are a bit complicated to fix like the one you have now.

what i usually perform first is to do a scan test and from there i start my own diagnostics with the aid of tech info

you need a qualified tech to handle the problem

[marv25]

even if the thermostat is at the warmest 32C, which is already heater, and mainit na yung lumalabas na hangin, umaandar pa rin yung compressor... I think i'm going to have it checked by a mechanic. i think thats why malakas sa gas yun compared sa ibang cars namin.

[L3GO]

mam, if malapit kayo s makati, try to bring your car at EMPIRE COOL located at 2251 don chino roces ave (formerly pasong tamo), para ma diagnos natin what talga problem ng car mo..

[marv25]

i'm in cebu. and im not a mam... thanks anyway...

[yapoy86]

marv25, climate control systems do not use Thermostat to control temperature..... it just mixes cold air and hot air from compressor and radiator that is why your compressor still works even if you set at the hot zone..

actually you have 2 evaporators there, one for the compressor (cold air) and another one for the radiator (hot air).. when you set the temp, the flaps adjust to control the hot and cold air mixture...

the only time it will stop is when the evaporator (cooling coil) reached temp of -5deg celsuis, it has an electronic thermostat that its main function is just to prevent the cooling coil from freezing...

You can have an Analog Thermostat to be installed to replace the electronic thermostat. Analog thermostat detects the cooling coil temperature via its probe then it has a dial where you can set the temperature... Or your set the climate control to MAX cold zone and manually turn-off the A/C switch when you feel cold and turn it ON when the cabin temp rises..

Do not rely on those climate control units...they are not applicable here in the philippines... better to install that analog thermostat..

if you will inspect your cooling coil housing you will notice there will be two wires going inside (check carefully since your Fan Resistor control is also installed in your cooling coil housing), this is the wire for the electronic thermostat... you can cut this, and connect it to the analog thermostat.. then insert the thermostat probe inside the housing and make sure it will be located past the air direction... (Fan -> Air direction -> Cooling coil -> Thermostat) or (Air direction -> Cooling Coil -> Thermostat - Fan) , then install the controller near the housing and set your desired temp... Analog thermostat will control the temperature by turning off or on the compressor.. once it reached your temp setting the compressor will disengage, once the cabin temp rises the compressor will engage..

Analog thermostat are very cheap usually 150 to 200 pesos only...

[marv25]

woah nice explanation there... but switching it to an analog thermostat wont be an option for us... well at least i know its normal...

When I set the temp to about 27-28C, its fine, not too cold or hot... but mabigat nga lang sa engine. I press ECON mode nga sometimes para lumakas ang hatak while overtaking, then balik sa AUTO. But yun nga lang hassle. And baka mabangga pa ako while pressing the button.

But hey thanks for the good explanation. At least I know its normal.

[den1106]

You can have an Analog Thermostat to be installed to replace the electronic thermostat. Analog thermostat detects the cooling coil temperature via its probe then it has a dial where you can set the temperature... Or your set the climate control to MAX cold zone and manually turn-off the A/C switch when you feel cold and turn it ON when the cabin temp rises..

Do not rely on those climate control units...they are not applicable here in the philippines... better to install that analog thermostat..

if you will inspect your cooling coil housing you will notice there will be two wires going inside (check carefully since your Fan Resistor control is also installed in your cooling coil housing), this is the wire for the electronic thermostat... you can cut this, and connect it to the analog thermostat.. then insert the thermostat probe inside the housing and make sure it will be located past the air direction... (Fan -> Air direction -> Cooling coil -> Thermostat) or (Air direction -> Cooling Coil -> Thermostat - Fan) , then install the controller near the housing and set your desired temp... Analog thermostat will control the temperature by turning off or on the compressor.. once it reached your temp setting the compressor will disengage, once the cabin temp rises the compressor will engage..

A classic way of hacking the system. Try to avoid this kind of modification as it will only add and create another problem.

cars nowadays are a bit complicated to fix like the one you have now.

what i usually perform first is to do a scan test and from there i start my own diagnostics with the aid of tech info

you need a qualified tech to handle the problem

The only way to go.

[marv25]

maybe i thought theres an electronic way to hack the climate control system... or i dont know...

[alwayz_yummy]

baka kulang na freon mo.

its easy to say na thermostat nga agad ang problem, kasi ako nong yun ang sinisisi ko agad. matibay ang thermostat ng nissan..

anyways, pacheck mo baka kulang lang yan ng freon.. pag kulang yan, have them trace the system for leaks. kung walang leak, baka due to age lang kaya nabawas.

[yapoy86]

woah nice explanation there... but switching it to an analog thermostat wont be an option for us... well at least i know its normal...

When I set the temp to about 27-28C, its fine, not too cold or hot... but mabigat nga lang sa engine. I press ECON mode nga sometimes para lumakas ang hatak while overtaking, then balik sa AUTO. But yun nga lang hassle. And baka mabangga pa ako while pressing the button.

But hey thanks for the good explanation. At least I know its normal.

*marv25, it will be better if you set the climate control temp to the MAX and adjust your temp by manual control (just be careful when the car is moving).... As i have said, HOT air is just mixed to the system and will just make your compressor WORK longer... When the system reached -5deg celsuis your A/C will automatically shut-off.. Try this at night especially when raining you will notice your A/C will shut-off but the cabin will be very very cold.. also check your AIR VENT Temp with a thermometer.. readings should be 9deg below (assuming your cooling system works fine)

my ride before can reach air vent temp as low as 0deg celsius during night with the thermostat at MAX setting..

A classic way of hacking the system. Try to avoid this kind of modification as it will only add and create another problem.



The only way to go.

what i have suggested is not hacking a "system" but rather improving what is already been there...Remember that car manufacturers usually DO NOT design their CARS based on Philippine Environment and some things are usually not applicable for us... It is better to know the system yourself and have possible options so that you can avoid A/C Techs giving you CRAP

all A/C units have "thermostats", they just differ in form and function... A/C units with climate control uses 2 common types of thermostat, 1: THERMISTOR or resistive type thermostat, LOW current control LOW VOLTAGE (just like what is installed to a Nissan Serena) when the system get cold (-5deg), the resistor will be in OPEN state and CLOSE when temp reaches 0deg and 2: FIXED Mechanical Thermostat, Low current control, (just like what is installed in Mitsubishi L300 Exceed Van) ... Other Cars without climate control uses Variable Mechanical or electronic Thermostat such as toyota vios, revo..

Thermostat even not in a Nissan vehicle usually lasts a very very loooong time... because they are in LOW Current application... usually when the system cooling efficiency drops, common causes are low charge, needs cleaning, leaks..

[marv25]

I dont know if kulang nga sa freon... very malamig naman yung lumalabas na air...

Before we used to leave the temp at 18degC and just adjust the fan speed... but at one point we found that the fan speed will adjust itself if we adjust the thermostat to our desired setting so we leave it at about 27C and when it's hot, the fan will be at high, and when it's cold, it will adjust accordingly... but yun nga lang hindi talaga tumitigil-trabaho yung compressor...

Climate control is not meant for the philippines talaga... sometimes while driving and it gets cold, the intake vent will open nga by itself to "let in fresh air"... but hindi dito applicable eh... biglaan na lang iiba yung smell ng air...

[marv25]

i dont understand lang why nissan designed the compressor to continue working even if its cold na... It would have been okay if the compressor would shut off when the desired temperature that is set sa thermostat is reached...

[Dark]

Kapag converted na ba ang thermostat ng Tucson ang performance ba ng compressor hindi na cya nag shushutoff when turning off the ac switch in the thermostat? Fan is off but compressor is still continuously working.


Or is there problem with the newly installed compressor? Or wiring?

Help please. TIA

[dr. d]

Kapag converted na ba ang thermostat ng Tucson ang performance ba ng compressor hindi na cya nag shushutoff when turning off the ac switch in the thermostat? Fan is off but compressor is still continuously working.


Or is there problem with the newly installed compressor? Or wiring?

Help please. TIA

incorrect wiring siguro.
have it corrected, po, before the compressor and/or tubings, get destroyed.