car ac working only sometimes


Asked by Mar 25, 2017 at 10:21 AM about the 2007 Toyota Yaris Base

Question type: Maintenance & Repair

my yaris 2007 car ac stopped working before 2 months slowly , means
sometimes work and some times doesnt work , and not at all . before 2
weeks i showed 2 car ac tachnicians both told to change control valve in ac
compressor . it is changed now and put new freyon gas and comprssor oil ,
now sometimes work sometimes doesnt , and also little smell inside . ac
technician told to replace the compressor and evaporator . so i met another
ac technician , he told to change ac pressure switch . again i met another
ac technician and he told to change ac compressor , clean pipes and
change condensor or ac radiator . Now i want to know
1) is it compressor problem or ac pressure switch problem ? (sometimes
work and sometimes doesnt)
2) smell is because of evaporator or condensor ?
3) sight glass of ac is not clear and dark , and technician told condesor or
ac radiator need to change . is it required to change condesor ?

5 Answers


Just get a pressure test on the AC system and be done with it. If you smell refrigerant inside you probably have a leak in the evaporator coil. The evap coil is inside the dash, it shares the plenum box with the heater core. The condensor is in the front end, sits in front of the radiator. Both could be tested for leaks. Instead of getting 50 different suggestions on what to change, have an AC tech test the system and replace the defective parts.


the problem is different answers is ac working sometimes and not working sometimes , is it problem of compressor or pressure switch ? how to know pressure switch is ok ? there is no leak anywhere , smell is like wet dust , so is it evaporator issue or condensor issue

2 of 2 people found this helpful.

They both have r134a refrigerant cycling through them, the only way to smell them is if they are leaking. If refrigerant leaked out, the system will stop working and not work again until it's fixed and recharged. If it is intermittently working, then you have a problem with the compressor and/or clutch, pressure readings are out of spec, an electronic fault/sensor, it might even be a faulty AC fan. You need a proper diagnose, take it to a shop that specializes in AC repair, a lot of neighborhood mechanics just aren't equipped for it. FYI, are you SURE you're smelling AC refrigerant/oil? The evaporator coil and heater core (both reside in the Heater/AC plenum box in the dash) can become musty or moldy over time, OR you have a leaky heater core that is giving off a smell as opposed to evap coil.

1 of 1 people found this helpful.

one ac technician told to change pressure switch . whenever ac button on , ac condensor fan and compressor becomes on , when ac button off , both becomes off , does it mean pressure switch is ok ? smell inside car is like wet dust . one technician told it is related to condesor and need to change . another technician told it is related to evaporator and evaporator need to change

1 of 1 people found this helpful.

Wet musty smell usually indicates a dirty a/c filter or dirty evaporator. When the system cools it removes moisture from the air and this will mix with dirt. Change the cabin air filter first before you pay someone to troubleshoot your system.

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