2013 LX570 No heat drivers side

[Crnick]

Hello, I tried searching, but could not find a thread with my symptoms. I have a 2013 LX570 that operates normally when cooling the cabin. I purchased it in the summer, and now that the mornings are cool, I'm not able to get normal heat to the drivers side of the car (both front and back).

I got techstream up and running, there are no fault codes in the system. Today I took a couple of pics of max heat and cool. The only odd thing (which might be a normal function) is the Air Mix Servo Targ being the opposite of each other. Perhaps some more informed eyes might see anything else amiss.

When AC on, max cold, both sides kick out 50 degree air. When AC on, max heat, drivers side will get to 80ish after 5 mins. Passenger will get to 150. If I turn the AC off, the drivers side will slowly creep up to low 100's. All temps were taken at the vents on each side of the head unit. Also, when asking for heat, it feels like its slightly less air on the drivers side (both front and rear), though I'm only measuring this with my hands and it could be a temp difference giving me that impression...

So far I've hit the sensor by the drivers knee with compressed air. I've also confirmed that the recirc flap operates correctly, and I've done the servo motor reinitialization. Any other ideas?

Thank you!

 

[soccernut]

long shot here as this is an old thread. Did anyone figure out this issue?
I am having exactly the same symptoms with my 2009 and I am finding no problems when scanning it with tech stream.

 

[Crnick]

long shot here as this is an old thread. Did anyone figure out this issue?
I am having exactly the same symptoms with my 2009 and I am finding no problems when scanning it with tech stream.

I have not. I've just been living with it set to HI on the drivers side. I've removed as much of the panels to watch the actuators and they seem to move similar passenger/driver. I've even timed them while manually actuating with techstream and there are no anomalies driver to passenger. At this point, I'm waiting for it to completely break so then hopefully there will be a clear direction to go.

 

[soccernut]

that's really weird.
How is the rear driver side heat? Mine is fine there as well.
The problem is only isolated to the driver front area only.

 

[Crnick]

My rear is just as weak as the front. Seems like whatever controls that side of the car isn't happy.

 

[ElJayBird]

Weird. I started noticing this on my 2014 a few weeks ago. It seems to come and go, almost like the heat will work fine for a while and then it shuts off on the driver side but the fan continues to run. I almost never mess with the thermostat but lately I’ve been noticing the drivers side is definitely not blowing warm air.

 

[STLandcruiser]

Following this now. Just got a 2013 about a month ago. Front blows hot and hard, but the rear never seems to heat up. It sure where to even start.

 

[soccernut]

Bumping this thread in case anyone has found a solution

 

[Crnick]

Bumping this thread in case anyone has found a solution

I still have not figured it out. I think the next step is the rip the dash apart to get to the blend doors. I just can't commit to that project without knowing exactly what the issue is.

 

[soccernut]

You can actually see the actuators moving if you stick your head by the gas pedal and look up (will need a light)
I looked around and tried to see if there is any issues and it all seems to be working fine.
the only thing that could happen is maybe the mechanism inside is no longer connected to the servo motor and is stuck on full outside air.

This is the only thing that makes sense to me since the temperature control works when its the requested temperature is equal to the ambient temperature or colder. I can never get it to be warmer than outside temp. This means that there is no blending of the air that goes through the heater core and is fully stuck on outside/AC air.

I am not fully confident of this theory but it's what I can come up with given all the diagnosing I have been doing

I have hooked up techstream and it all checks out for expected values from the servos.

 

[soccernut]

Bringing this thread again from the dead.
I removed a bunch of the dash out to try and see if the air mix servo is operating correctly. Seems like everything is fine on that end. It moves throughout the whole range of temperatures and tech stream values check out.

I checked the coolant level and it was a bit low. Not sure if that would affect only the driver side heat as the passenger side blow nice and hot.

The only think I am could think of is that there is a mechanical part that isn't engaged on the servo or there is some damage on the inside of the blend door.

Really hope there is someone here who has figured it out and can help.

 

[soccernut]

SOLVED!!!!!!

It was a coolant passage that was plugged. A simple flush fixed it.

 

[Crnick]

SOLVED!!!!!!

It was a coolant passage that was plugged. A simple flush fixed it.

Thanks for updating. I plan to flush replace the coolant when I do my next oil service. Did you do a drain/refill? Or an actual flushing product?

 

[Markuson]

Not even one, “Ain’t hot no gas in it” Slingblade quote? Amazing!

 

[soccernut]

Thanks for updating. I plan to flush replace the coolant when I do my next oil service. Did you do a drain/refill? Or an actual flushing product?

It was a flush. They said there was some debris in the lines than they needed to get out.

 

[CanadianRockyCruiser]

It was a flush. They said there was some debris in the lines than they needed to get out.

Debris in the coolant lines...that does not sound good.

 

[bloc]

Debris in the coolant lines...that does not sound good.

Also I can't see how that would impact one side of the dash but not the other. There is only one heater core in the dash with the blend doors being responsible for what temp air goes where.

Either way now it works, so they did something worth while.