Strange noise linked to AC
10-16-19, 04:34 PM
#1
Driver School Candidate
Thread Starter
Strange noise linked to AC
Hi there fellow Lexus owners. I am new in the club and just recently bought a used late 2014 Lexus IS300H. I am extremly satisfied with the car and it keeps suprising me every time i drive it.
However I have a strange issue that i started noticing quite early. Sometimes when i start the car, most often occurs when its not been on for the day, i hear this strange noise which will try to describe shortly. I didnt put my mind too much into it as it only was present for a few 1 2 secounds each time and only once.
Now a few days later I started to fiddle with the AC controlls to learn how it works and started to notice that this specific sound occurs each time I change vent output and if i switch temperature beyond a certain point. 19 to 20 C and vise versa was what i noted. I have switched it before but never noticed the sound. Perhaps because of the radio and the car in motion that masques the sounds as this time i was parked with ignition only.
Now to the sound. The best way to describe it is the sound an old leather couch or chair can make when you sit down. Almost like a farting sound. When i tried listening closer to the dashboard i can hear some mechanical parts moving as well so my guess is that it could be some issue with a ventlid or a relay. It sounds like it comes from either under the gearshift and ac area or perhaps further back under the driving mode controller. I have only limited car experience and even less with Lexuses and have no idea how this sound could relate to this. Maybe something that has to be lubricated? It just sounds so strange to me, but the AC and rest of the car works flawlessly in othet matters, as far as I know atleast.
Hope that i can find some ideas from you guys!
Video:
However I have a strange issue that i started noticing quite early. Sometimes when i start the car, most often occurs when its not been on for the day, i hear this strange noise which will try to describe shortly. I didnt put my mind too much into it as it only was present for a few 1 2 secounds each time and only once.
Now a few days later I started to fiddle with the AC controlls to learn how it works and started to notice that this specific sound occurs each time I change vent output and if i switch temperature beyond a certain point. 19 to 20 C and vise versa was what i noted. I have switched it before but never noticed the sound. Perhaps because of the radio and the car in motion that masques the sounds as this time i was parked with ignition only.
Now to the sound. The best way to describe it is the sound an old leather couch or chair can make when you sit down. Almost like a farting sound. When i tried listening closer to the dashboard i can hear some mechanical parts moving as well so my guess is that it could be some issue with a ventlid or a relay. It sounds like it comes from either under the gearshift and ac area or perhaps further back under the driving mode controller. I have only limited car experience and even less with Lexuses and have no idea how this sound could relate to this. Maybe something that has to be lubricated? It just sounds so strange to me, but the AC and rest of the car works flawlessly in othet matters, as far as I know atleast.
Hope that i can find some ideas from you guys!
Video:
Last edited by Easterlily; 10-16-19 at 05:21 PM.
10-16-19, 06:57 PM
#2
Lexus Test Driver
Join Date: Feb 2017
Location: Richmond Hill, Ontario, Canada
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Welcome to the forum!
It definitely sounds like the servo motor on the HVAC box moving the blend doors.
Usually they can be heard if there is no ambient noise, but I have to admit yours does sound a little louder than normal.
If you kneel down outside the car and put you head in the drivers and passengers footwell, you should be able to hear it even louder...this will at least tell you which servo it might be.
Either the motor is struggling to move, of the blend door is struggling to move.
It definitely sounds like the servo motor on the HVAC box moving the blend doors.
Usually they can be heard if there is no ambient noise, but I have to admit yours does sound a little louder than normal.
If you kneel down outside the car and put you head in the drivers and passengers footwell, you should be able to hear it even louder...this will at least tell you which servo it might be.
Either the motor is struggling to move, of the blend door is struggling to move.
10-16-19, 11:23 PM
#4
Intermediate
10-17-19, 07:59 AM
#5
Lexus Test Driver
probably blend doors or other servos/motors. the plastic flaps usually have a rubber seal and maybe it's just dry around where the rubber drags. fixing that would likely involve pulling the dash. i'd say just live with it and move on. not worth all the fuss unless you're under warranty still.
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