A/C performance test

[Linas.P]

Got my A/C service today, it wasn't working for a while just didn't get to fixing it as it wasn't necessary in current weather. Now it got re-gased, I added anti-bacterial clean as well and they did performance test. Everything passed car ready to pick-up.

Got inside, turned heater to "HI" for 5 min before it got uncomfortably warm in the car, turn A/C on "LO" and re-circulation. What would be your expectations?

Should it start blowing cold air straight away or should it gradually get from hot to say "mildly warm". My expectation was that it would blow freezing cold air almost instantly ~10-20s (that is what it was if I remember it right). Just because it wasn't working for few months I am now confused, maybe it should work gradually like that and maybe it wasn't that cold as I remember?

Looking for some quick replies as I am thinking to go back to A/C place and challenge them on their "performance test".

[madasahatter]

7 minutes ago, Linas.P said:

Got my A/C service today, it wasn't working for a while just didn't get to fixing it as it wasn't necessary in current weather. Now it got re-gased, I added anti-bacterial clean as well and they did performance test. Everything passed car ready to pick-up.

Got inside, turned heater to "HI" for 5 min before it got uncomfortably warm in the car, turn A/C on "LO" and re-circulation. What would be your expectations?

Should it start blowing cold air straight away or should it gradually get from hot to say "mildly warm". My expectation was that it would blow freezing cold air almost instantly ~10-20s (that is what it was if I remember it right). Just because it wasn't working for few months I am now confused, maybe it should work gradually like that and maybe it wasn't that cold as I remember?

Looking for some quick replies as I am thinking to go back to A/C place and challenge them on their "performance test".

When i have had a regas it blows around 4 deg on coldest setting. What you must remember in the summer its warmer out. so the air con naturally feels colder when

set on cold. Any transition from hot to cold air will not be instant, as you say X amount of seconds is not unreasonable.

[Linas.P]

Yes.. that is why I started doubting myself...

The point is that I use re-circulation, so I heat the cabin up-to say 28C, then turn A/C on low, give maybe 20s and check if I can notice difference between the air in rather hot cabin and air coming from the wents... I am not sure how cold it should be, but I expect it to be noticeably colder. What is happening now it is hardly any difference... and even after 5 minutes it gets just mildly warm (~21C), but does not get noticeably colder. 

Just checked again... and I guess most telling thing is that when I turn temperature to "LO" without A/C it obviously blows the same hot air, then I turn on A/C and it should start cooling, but literally there is no difference in temperature whenever A/C is on or not.... I am certain that cannot be right. I think the only reason it gets colder after 5 min is because it is like 7-8C outside and car cabin naturally cools down over that time.

[NemesisUK]

My handbook states that when the outside air temperature nears 0c the A/C will not function, as in the chiller will not operate.

Could this be what's happening in your case?

[Linas.P]

I am not sure, I was wondering if this could affect it. But the temperature is more around 8C now... ~11C in garage.

If that is the case I wonder how can I check if A/C works at all or not?

[Ala Larj]

Just popped out to check mine and when I go from max hot to max cold it takes a couple of seconds to change but when it does it's very cold.

Air temp is 6 deg according to dash.

[Linas.P]

So pop back-in and told them to check again.

I tend to believe they tested the performance with fresh air from outside which is 7C, but when I told them to set it to re-circulation it was obvious A/C doesn't do anything. So they re-gased it again... still nothing, they then ran full diagnostics and found following "B1423 - Refrigerant pressure sensor circuit defective". Now that means that pressure is too high, too low, sensor is faulty or A/C ACU is faulty.

If I would believe they properly re-gased it to correct pressure, then the next thing to check is sensor as ACU is unlikely to fail. Now do I trust them? Not really.. but I guess it is worth checking/replacing sensor anyway?

Anyone did it before? 

[Linas.P]

So all in all, A/C guys done full diagnostics and troubleshooting again and concluded it is faulty pressure sensor.

• They quoted £490 for part + fitting (bear in mind that is 1 screw) 
• Lexus quoted £270 for part
• The actual part is $12 on eBay (original DENSO ~$25)... just need to wait for it to be posted from US.

My plant is to get maybe original DENSO... or maybe try local breaker (just because it will be significantly quicker than wait for it to arrive from US).

Any other ideas?