dworak

Hi!

I own Lexus RX330. A/C compressor cycles on and off on idle when A/C Auto mode is engaged. 9 seconds 'off', 11 seconds 'on' at 70F ambient. Is it by design or I am experiencing a problem? In terms of the ability to supply cool air A/C is fully functional.

Thanks in advance!

nedogre20

I have always had the same problem with the Rx330 and could never figure out why it does that. When the ac compressor comes on, it blows out ice cold air. When it cycles off, it would blow out air not nearly as cold. Anyone else have this problem?

litzdog911

I think that's just how it works.

robbyk

That is how your A/C works.

Mine was doing the same thing when the outside temperature is around 70. When summer time came we had couple of days of over 100 degrees. Surprisingly the A/C compressor stayed on all of the time to the point that was making my wife cold.

nedogre20

I live in Texas and the summers are absolutely brutal with the temperature being well over 100 for consecutive days and the ac acts the same regardless of temperature.

robbyk

Then something is wrong with the A/C. If it is low in freon it will do what you are describing. However freon does not disappear or breaks down, if it is low there is a leak somewhere.

I could also be an A/C relay. The relay is very easy to replace and very inexpensive.
First thing to do is to check level of freon in the system.

nedogre20

Ya the next check will definitely be for refrigerant or any leaks. Thanks

dworak

This is an update. I went to a shop that does air conditioners and asked to service the refrigerant. What this means is they pull refrigerant out, weigh it and then inject it back to the system topping up to a necessary level if needed. In my case they added 30%. They told me that it's normal for a 10 year-old car to miss this amount of refrigerant.

What has changed? Nothing it terms of compressor behavior and in terms of conditioner cooling efficiency. However, it suddenly fixed the issue with automatic transmission that I've been experiencing for quite a long time: sudden jerks and gear hunting at low speeds. The engine works much smoother, it's noticeably less noisy now.

nedogre20

I'm not an expert when it comes to cars but what does the compressor have to do with the transmission acting up?

dworak

Compressor causes increased engine load and, what is more important, engine load fluctuations. This affect RPM and as a result transmission may behave differently.

nedogre20

My transmission has always had a jerk in it from day one even with the AC being off. I've done all the fluids,timing belt, and reprogrammed the ECU and its still the same result. It's not a big deal to me unless the transmission starts to slip but there is no sign of that yet.