climate control ECU problem.

[lexs470]

I am trying to replace the climate control ECU due to the problem I am experiencing with the heating.
after the recent service to the 01 lx470 was done at the dealer, I had smelled a burning circuit smell from under the dash. I am sure it had something to do with the climate control circuitry as this is what has happened afterwards.
the defogger is not defogging properly, the intensity of the heat coming from the foot wells even at moderate temparatures of 73 in auto mode is so svere that it becomes uncomfortable. I have to switch to defog or other modes to take the heat away from the foot wells. if the temp is decreased further the a/c turns on and the front wells open up with cold air.
hence not normal.
the dealer, as always, is not much help.
I would like to know if someone has the schematic diagram for the location of the cliamte control ECU. the lx has nav therefore it might be a little different than the ones without the nav.
any help would be much appreciated.

 

[Jukelemon]

Friend:

1- Your dealer works for you. The idea of them not disclosing what was completed on your car is complete BS and should not be tolerated. Do not get pushed around by a dealer.

2- I am not certain that your issue is unusual. I still have not heard what happens to you when you take the controls off of Auto and you adjust the temp/fan in manual mode. The system is far from perfect and even mine has funky temp settings that produce more or less heat than I think they should. BUT. the manual settings prove to fine when trying to fine tune your cabin temp.

Juke

 

[fj55-100]

pm me your e-mail for a EWD

symptoms are similar to what hapens when you leave the inside ambient temp sensor unpluged ,
it puts the ecu into a fixed program ,
happens alot when someone is in the dash to do othe repairs --
the sensor is a two pin located on the right side of the lower dash kick panel directley below the key cylinder ------ look where the air slots are cut in the dash and remove that cover until you see the temp sensor , i think it also has a small convolute tube on the same sensor ---
it must be pluged in for the climate controle to work
Fj55-100

 

[lexs470]

thanks for the replies.
1. the dealer i am dealing with seems to be the "only" dealer a bit better than others. I had terrible experience at lawrence lexus service dept. they were worst than ever.
well at the moment i'm trying a different dealer but without much luck. the tech's are totally incompetent. the first time they opened up the cluster to replace a bulb, they left the combination meter's connections lose.
now when i'm complaining about the unusually high temp inside the cabin. the tech gave me a lot of BS initially when i told them they could've fried the ECU. he said there are no error codes coming up. would the sensor not connected result in an error code.
now they tried to run around that problem by saying that they compared to another LX (diff year) and they "think" that it's working fine.
i've been dealing with this for the past two months now and i can't figure out how to have this situation fixed other than to get this done myself. there's only so much there is to the auto climate control and i'm sure can be figured out.
i look forward to your input.
thnx again.

 

[NMuzj100]

Typical untrained "tech" BS. "I only know how to remove and replace parts. In this case the service manager told me the part was too expensive to replace under warranty so there must be no problem."

 

[Jukelemon]

55 seems to be on to something. Regardless, I would give corp Lexus a call. That is just not acceptable-especially for Lexus

 

[lexs470]

totally agreed. given the parts are expensive they're hesitant to replace. I called lexus corp. and had their rep come in to look at it personally. for some reason the rep. was not a technical rep. he was a business relations rep. who knew little about cars. nevertheless the truck's back at the dealer to be looked at. in the meanwhile, i will start investigating the electrical flow chart to figure out what's causing this.
i'm sure one of the circuits were fried and have now caused this.
as for the sensors not plugged in, it was mentioned that they have to be plugged in in order for the climate control to work. given that the acc is infact operational, just generating more heat than usual i'm curious if the sensor can be ruled out or not.

 

[lexs470]

well the dealer called. said couldnt find anything wrong with it so i picked it up and drove home. on the way back the weather was better than usuall so I turned the heat down a bit to get some fresh air. down to 70, then 68, then 65... but the center dash vents kept blowing luke warm air and the side vents were throwing colder air. that's just not right.
the center vents should only be throwing out cold fresh air when the temp is down to 65.. anyhow i then put the temp control to 'max cold' and all of a sudden i heard some vents pop open and in came the gush of fresh air...
my question now is... what could be causing this issue..
is it the climate control ecu, or some other ecu.../ part.. ?