HKTaz

I'm new to this forums and have a problem need some help here.

I have a 2004 2nd generation Toyota Harrier (Lexus model RX330). The A/C blowing hot air if temperature is not set to Max Cold. This happened no matter whether turn on the A/C with Auto or Manual setting. This case also happen no matter whether setting the A/C system to Dual mode or not, no matter whether turn on or off the air intake control button. As long as A/C on, cold air only come out when temperature set to Max Cold, even if set to 18 degree, full hot air come out. Another thing is, say I have the A/C on, set to max cold, cold air came out from the front vent, but after I try to increase the temperature to say 18 degree, the hot air flow will change to Floor/Windshield mode.

Any idea what's wrong? Could it because due to the change of the battery? Is there anything need to reset after replacing the battery?

Thanks in advance for any help.

mandyfig

Sounds like your temperature controller is acting up. Take it to an AC place.

It appears that the AC is only triggered on the MAX setting and any setting other than will result in the Heating. Hence your servo triggers to a foot setting.

HKTaz

Thanks mandyfig. So it sounds like I need to fix one or all of this??
http://lexus.sewellparts.com/accesso...2004/4620.html

mandyfig

Sorry I may not be able to diagnose. It could be one of these but I think it might be another thing. It could just be a sensor. Best bet take it to an AC place if you do not want to take it in to Lexus dealer.

In my case one of the servo's was replaced due to a ticking noise. Otherwise my AC was just fine.

willdogg

HK,

Here's something you could try (checking your AC Diagnostic codes):

http://www.lexls.com/tutorials/air/accodes.html

It won't fix your problem, but it could help you isolate it or narrow it down.

good luck

HKTaz

Thanks mandyfig once again.

Thanks willdogg, the link is useful and after following the steps, my system return code 11 and occasionally return code 24. From the website code 11 related to "Open or short in room temperature sensor circuit", but what is code 24 means? Do you have any idea? Anybody?

HKTaz

Oh, another thing interesting is, the problem with my car (blowing hot air) happen no matter whether A/C is on or not. That is, even with A/C is off, the car will blow hot air at any temperature setting other than Max Cold. This may help to isolate the problem, that is, not really A/C related?

willdogg

Sounds like you might have a bad relay. Check this old link:

http://www.justanswer.com/lexus/2391...gx470-suv.html

He was having a similar problem with his GX. Here's what he did:

1. Got the $80 relay from a Lexus or Toyota dealer
2. Open the hood
3. Open the under hood fuse/relay block cover
4. Remove the Relay labeled a/c magnetic clutch which will have a part # XXXXX on it, throw that relay in the garbage
5. Install relay part # XXXXX that you will purchase from a toyota or Lexus dealer.
6. You're done.

hope this helps

HKTaz

Thanks willdogg. Not really 100% same case as the GX guy because my A/C switch doesn't blink and the a/c stays cold as long as temperature is set to Max Cold. But anyway I'll check on the relay first. Thanks once again.

HKTaz

Finally find some time to look further to the problem. After reference to the repair manual with code 11, found out actually the problem is the connector to the temperature sensor is not functioning. Clean up the connector with some contact cleaner, plug it back to the sensor. Now I have the A/C system back! Thanks for everyone's help.

Carver

That's good to know, thanks for posting back.

willdogg

oh man, that's great news.

alik99

HK, i think i've got the same problem but in '07 RX. Where do I fine the sensor/connector that has to cleaned? Thx!

HKTaz

If you also have the Code 11 after going through the system diagnostic, then according to the repair manual, the trouble area will be either:
- Cooler thermistor (the sensor)
- Harness or connector between cooler thermistor and A/C amplifier
- A/C amplifier

I don't have my car with me at the moment so I can't attache a photo here, but the sensor actually is not very difficult to find. It's next to the steeling column, just in front of your right knee, you'll see a small cover with few horizontal parallel interstice, not very big in size, just as big as your thumb.

You can take a look on the photo posted by mctufts in the thread Removing center console underneath shifter- DIY. Look at the photo "Picture of dash being pulled away".

I didn't try to remove the cover as shown in the photo, I did the cleaning on the connector from the back, get hands behind from underneath.

Hope this help.

mschluns

ai had similar problems with my 04 rx, my problem was related to a radiator leak...The car didnot overheat but the radiator level was low enuf to screw up the cooling/heating controls...there is a recall on these radiators, Lexus replaced mine in 2010...