I have a 2002 sc430 with 225000 miles. About a week ago My wife and I took a 4 hr trip. During our trip the weather started getting warm so I decided to turn on the air-condition to 68F. 15 minutes after i turned on the air-condition my wife started to feel very hot air coming from hear feet area... I know we have all complained about hot air from the feet area but this was different. She also felt hot air coming from the top vents but only from her side.


I lowered the temp to 65, turned it off and on again, changed where the air coming from and clicked on the dual button to see if that would help but nothing. M side was perfect and when I lowered the temp my side was ice cold.
Has anyone encountered this issue? I have owed this car since new and this is the first time this has happened.
Thank you

 

Seems like BGW encountered something similar that required the replacement of a mixing valve motor (or something like that). Others have reported it also. Of course, I could be confusing this with an over all temperature problem rather than a focused problem on one side only.

 

Guesses on my part:

I'm guessing you have a problem with the passenger side airmix servo. I'll add a drawing from the FSM below. Also hoping someone who has had the problem looks in and posts.

Without input from others more knowledgeable -- You might be able to perform a diagnosis by removing the glovebox and switching the system from heat to AC and see if the servo moves around. Keep in mind the passenger side also has a mode control servo (control where air comes out).

I had to replace my mode control servo but did not look into how hard it would be to do the air mix servo.

 

It could be a low charge of R-134. One side blowing hot is a common sign.

You need a gauge to check though. You can rent one for free from many auto part stores, but then have to youtube how to use it.

 

hlthlnk,

Just a dumb question, is the temperature both sides in sinc? If they are, then my guess is the temp control on the passenger may be in question. Try to adjust the temp just on the passenger side to see if it makes any different.

 

Thank you for all the suggestions.

GmanSC- I tried every possible combination and the passenger side remains hot. The driver side does what it should do based on the temp I set.

I did find this post:

 

You shouldn't listen to that guy, he doesn't know anything.(HA HA)

What did the self test show?

 

After disconnecting the battery I listened closely for any sounds and I did get that constant little buzz coming from the passenger side.
The next thing is to try and remove the "servos" and try to fix them.
Thank you!

 

I replaced one in my IS250 and it wasn't too bad. Here is a video

It isn't the best video you can watch but it is an SC430.
If you are going to do it yourself, I would watch some of the other "Lexus A/C Servo" or "lexus Blend Door" Videos

 

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