04 Gx470 Heat/ac servos help (1 Viewer)

[Augustiron]

Hey there all,
I did a search for the keyword "servos" and read all the threads but didn't find the information I needed. Most are trying to diagnose noises from the servos.

Problem:
'04 GX470 non nav, has a recent problem with not getting heat out the driver's floor, only blows cold air regardless of the settings. Wifey is not happy.

I realize there are four different servos for the different operations of the AC / heat. I was wondering if anyone had any guidance on which one would be suspect?

I ran the AC system self diagnostic by holding the 2 buttons as outlined elsewhere on the forum, but got no error codes.

Thanks in advance

 

[Charles63]

Hey there all,
I did a search for the keyword "servos" and read all the threads but didn't find the information I needed. Most are trying to diagnose noises from the servos.

Problem:
'04 GX470 non nav, has a recent problem with not getting heat out the driver's floor, only blows cold air regardless of the settings. Wifey is not happy.

I realize there are four different servos for the different operations of the AC / heat. I was wondering if anyone had any guidance on which one would be suspect?

I ran the AC system self diagnostic by holding the 2 buttons as outlined elsewhere on the forum, but got no error codes.

Thanks in advance

 

[Charles63]

I have an 03 non nav. My mode servo is clicking, but defrost and ac work, so I’m not doing anything now. My sons mode servo was out on his 04 4Runner. I couldn’t have done it, he’s got smaller hands and is a lot more agile. Here’s a thread that I pilfered from this forum that is a reference DIY glove box removal video and AC blend door (mode) motor replacement - ClubLexus - Lexus Forum Discussion - https://www.clublexus.com/forums/gx-1st-gen-2004-2009/923450-diy-glove-box-removal-video-and-ac-blend-door-mode-motor-replacement.html

 

[Augustiron]

I figured it out.
Heat everywhere except driver's floor under any mode setting made it pretty clear it was the one servo at the driver's footwell.
Easy fix.
- pop off the plastic trim aside the gas pedal, pull directly out on the rear part of it at the vertical seam as there is a slide-in tang forward. Pop out at the seam and slide rearward to release the tang.
-servo very obvious with just 3 screws
- I dismounted it and left it plugged in and cycled all the different modes and I can see it struggle to move but not move the arm.
- When I had it on the bench and took it apart. The stepper motor contacts are not visible as they are on the underside of a large gear, and do not appear to be serviceable to clean as the gear would need to be removed from the body, but the arm is glued on to the shaft of the gear on the outside of the case, so no way to remove it to clean the contacts easily. I thought about bending a cotton swab with contact cleaner to get in there but I wanted to be sure it was good so I just opted to replace it.
- RockAuto has the servo for $97 (dorman 604341), my local O'Reilly was willing to price match that with their house brand which normally retailed for $140 with a lifetime warranty.

Currently waiting for the part to arrive so I can reinstall it

 

[Charles63]

I figured it out.
Heat everywhere except driver's floor under any mode setting made it pretty clear it was the one servo at the driver's footwell.
Easy fix.
- pop off the plastic trim aside the gas pedal, pull directly out on the rear part of it at the vertical seam as there is a slide-in tang forward. Pop out at the seam and slide rearward to release the tang.
-servo very obvious with just 3 screws
- I dismounted it and left it plugged in and cycled all the different modes and I can see it struggle to move but not move the arm.
- When I had it on the bench and took it apart. The stepper motor contacts are not visible as they are on the underside of a large gear, and do not appear to be serviceable to clean as the gear would need to be removed from the body, but the arm is glued on to the shaft of the gear on the outside of the case, so no way to remove it to clean the contacts easily. I thought about bending a cotton swab with contact cleaner to get in there but I wanted to be sure it was good so I just opted to replace it.
- RockAuto has the servo for $97 (dorman 604341), my local O'Reilly was willing to price match that with their house brand which normally retailed for $140 with a lifetime warranty.

Currently waiting for the part to arrive so I can reinstall it

I misread your original post, I was thinking passenger side. Good to know at least one of servos is reasonable to access.

 

[Augustiron]

Crap, well I didn't figure it out.

I replaced that driver's side footwell servo with a new one and it's still doesn't activate under any of the climate control settings.
Nothing I could do could get that arm to move on the servo when plugged in.
The flapper it attaches to moves freely, but I don't know how to electrically test the input to the servo.
It is a 5 wire plug So it has power and ground, but he stepper sensors probably take up the other three.
I ran the diagnostic modes sensors and servos and everything shows fine.
I can hear the other servos activating as I I move through the climate control settings.

Is this driver's side one dependent on another one working and sending a signal, sort of as a slave to another servo?

I am feeling really frustrated here as I have done a ton of searching I'm and have come up empty.

I pride myself on being a good mechanic And I've worked on fleets of cars and Land cruisers, but this has me flummoxed and I might be making an appointment at the local Lexus dealer and letting them set my credit card on fire.

Any and all ideas welcomed.

 

[Charles63]

Crap, well I didn't figure it out.

I replaced that driver's side footwell servo with a new one and it's still doesn't activate under any of the climate control settings.
Nothing I could do could get that arm to move on the servo when plugged in.
The flapper it attaches to moves freely, but I don't know how to electrically test the input to the servo.
It is a 5 wire plug So it has power and ground, but he stepper sensors probably take up the other three.
I ran the diagnostic modes sensors and servos and everything shows fine.
I can hear the other servos activating as I I move through the climate control settings.

Is this driver's side one dependent on another one working and sending a signal, sort of as a slave to another servo?

I am feeling really frustrated here as I have done a ton of searching I'm and have come up empty.

I pride myself on being a good mechanic And I've worked on fleets of cars and Land cruisers, but this has me flummoxed and I might be making an appointment at the local Lexus dealer and letting them set my credit card on fire.

Any and all ideas welcomed.

Dang, I was hoping you had it. It’s been a few months since I’ve been in my sons sr5 4Runner but I don’t think he has the dual climate control ( 04 ). I think he just has 2 servos. Man, I hate going to the dealer; but when we had a local mechanic replace his timing belt/ water pump we didn’t save much

 

[UNCnalledge]

@Augustiron did you figure this out? I have had this exact same issue for a couple of winters and it’s on the list to tackle this year.

 

[Charles63]

@Augustiron did you figure this out? I have had this exact same issue for a couple of winters and it’s on the list to tackle this year.

I have not addressed this ( just let my son take the gx to Denver).

 

[Duke1]

Hey there all,
I did a search for the keyword "servos" and read all the threads but didn't find the information I needed. Most are trying to diagnose noises from the servos.

Problem:
'04 GX470 non nav, has a recent problem with not getting heat out the driver's floor, only blows cold air regardless of the settings. Wifey is not happy.

I realize there are four different servos for the different operations of the AC / heat. I was wondering if anyone had any guidance on which one would be suspect?

I ran the AC system self diagnostic by holding the 2 buttons as outlined elsewhere on the forum, but got no error codes.

Thanks in advance

I'm hoping in all your research that you could help my diagnosis- in my '04 Gx470, the air temp and blower works great but I can not get the air to go to the feet or the defrost- it stays coming through the vent regardless of what mode is selected. Do you happen to know the actual name of the part or servo that I need to replace? ("Mode Servo" is the only thing I was able to find referenced online but that doesn't seem to be an actual part I could order)

 

[Charles63]

I'm hoping in all your research that you could help my diagnosis- in my '04 Gx470, the air temp and blower works great but I can not get the air to go to the feet or the defrost- it stays coming through the vent regardless of what mode is selected. Do you happen to know the actual name of the part or servo that I need to replace? ("Mode Servo" is the only thing I was able to find referenced online but that doesn't seem to be an actual part I could order)

Sorry, I don’t remember the name of that servo, or if it’s identical ; but my son has/ had an 04 v8 4Runner that wouldn’t switch to defrost ( seems like that would be default for safety reasons). He was able to change it fairly quickly, but he has smaller , steady hands. It was behind the glove box and there were a few cable ends to connect. I think I bought it from parts geek. It wasn’t much. I’ll see if I can find it

 

[Duke1]

Sorry, I don’t remember the name of that servo, or if it’s identical ; but my son has/ had an 04 v8 4Runner that wouldn’t switch to defrost ( seems like that would be default for safety reasons). He was able to change it fairly quickly, but he has smaller , steady hands. It was behind the glove box and there were a few cable ends to connect. I think I bought it from parts geek. It wasn’t much. I’ll see if I can find it

Mine won't change to defrost or floors and from what I have seen on videos and small hands do look key to performing the repair. I found a part called the Blend Door Actuator... perhaps that is what your son replaced?

 

[Charles63]

I believe its called the hvac mode servo, at least on his 4runner it was. We bought a cheap replacement( like $30). I can't find the receipt. There's a video on youtube. I'm not 100% sure if it's the same on a gx, but I thought the the blend door was for fresh vs recirculate?

 

[Charles63]

It's not uncommon for a damper motor to have gone bad. Run the A/C system diagnostics:

Hold the A/C and recirc buttons, then turn the key on. After a few seconds the system will cycle through its diagnostics. It is normal to see code 21 - Solar Sensor if you are in a garage or carport, and not in direct sunlight.

Post any codes you see.

Chip H.

I totally stole this from club lexus

 

[Augustiron]

Just getting back to this thread, I didn't realize there were responses to it.

I did the diagnostic mentioned above (hold the auto button + recirc on my non nav) and have codes 21, 24 and 46 saved

 

[Augustiron]

I just.looked up code 46

46: Air mix door servomotor circuit (driver's side)

That makes sense.
What doesn't make sense is why the replacement one I got did the same exact thing the existing one did where it seemed to receive a signal but didn't move more than a hair even when removed from the blend door and hanging loosely in hand....

 

[Nitti69]

I just.looked up code 46

46: Air mix door servomotor circuit (driver's side)

That makes sense.
What doesn't make sense is why the replacement one I got did the same exact thing the existing one did where it seemed to receive a signal but didn't move more than a hair even when removed from the blend door and hanging loosely in hand....

Hello Augustiron, thank you for the descriptions above, they’ve Ben very helpful!
I pulled the codes from my ‘04 GX470, I have a codes 21(solar) not an issue, 24 which I read is the compressor clutch relay (vehicle was off, AC compressor works great) and a code 36 which I haven’t had success defining. Do you know what this code represents? My drivers footwell servo is hunting and the recirculating (inside / outside air) clicks rapidly if it’s on inside air. I’m trying to locate the service I need to replace before I take it apart. Any help is greatly appreciated!
Thank you

 

[Augustiron]

I poked around the internet and couldn't find any info for code 36 for a lexus / Toyota AC. Sorry

 

[Nitti69]

I poked around the internet and couldn't find any info for code 36 for a lexus / Toyota AC. Sorry

Thanks for checking much appreciated!

 

[bioboyd]

While troubleshooting a similar issue with my '03 GX, a YouTuber/Lexus sedan owner emphasized that blend door actuators must be replaced with OE...something about incompatible signals in aftermarket actuators. Does that sound right to anyone? Thx