Heater issues
I have a long saga. Maybe my RX 350 2011 is ready to be terminated
here is the sequence of events
1) hvac controls takes several minutes to boot up
2) passenger side only blows hot air
3) air conditioner doesn’t work
replaced the HVAC amplifier
tried to replace the servo, that was mess an relized it can’t be done. Put it all back together. Tried to plug in a new servo and it didn’t work either
now i get hot air in the vents all the time.
I’m so frustrated, I wanted to keep this car running longer
thanks
Matt
here is the sequence of events
1) hvac controls takes several minutes to boot up
2) passenger side only blows hot air
3) air conditioner doesn’t work
replaced the HVAC amplifier
tried to replace the servo, that was mess an relized it can’t be done. Put it all back together. Tried to plug in a new servo and it didn’t work either
now i get hot air in the vents all the time.
I’m so frustrated, I wanted to keep this car running longer
thanks
Matt
my initial thought is a blend door actuator. yes they are a pain to fix but if you want to keep the car and its in good condition and well maintained then the cost to repair is worth it. even if you trade it for a similar vehicle with no cash upfront you may have issues with a new vehicle. the most economical IMO unless youre planning to get a new vehicle anyway because the repair isnt cheap at a dealer
Do you know if the A/C compressor turns on? Did you check the refrigerant charge? Did you check your coolant level?
If the compressor is not turning on, it may be that the flow sensor has become demagnetized with age, and there is a trick where you place a small magnet on the sensor to force the compressor to operate.
Many members have done this.
See below:
https://www.clublexus.com/forums/rx-...ac-issues.html
This link goes deep into the diagnostic procedure.
https://www.clublexus.com/forums/rx-...fo-inside.html
https://www.clublexus.com/forums/rx-...t-running.html
If the compressor is not turning on, it may be that the flow sensor has become demagnetized with age, and there is a trick where you place a small magnet on the sensor to force the compressor to operate.
Many members have done this.
See below:
https://www.clublexus.com/forums/rx-...ac-issues.html
This link goes deep into the diagnostic procedure.
https://www.clublexus.com/forums/rx-...fo-inside.html
https://www.clublexus.com/forums/rx-...t-running.html
Last edited by Clutchless; May 26, 2026 at 06:02 AM.
Proper diagnosis is required. Is it worth spending money in doing the diagnosis, or just keep throwing parts till it gets fixed or throw in the towel is what you need to decide.
If you are open to speculations ... mine is that there is communication failure with or within the env-control function. I wish I knew more ... if such a module exists separately or is part of the ecu. Usually there is a communication protocol by which all functions talk to each other. [This conclusion/speculation is based on what you stated ... heavily biased on user input]
I would disconnect battery for 30min or so to clear out gremlins if any and see if the communication is reestablished.
Best advice from me would be:
Take the RX to some one who knows how the A/C communication works and let them diagnose the problem.
Salim
If you are open to speculations ... mine is that there is communication failure with or within the env-control function. I wish I knew more ... if such a module exists separately or is part of the ecu. Usually there is a communication protocol by which all functions talk to each other. [This conclusion/speculation is based on what you stated ... heavily biased on user input]
I would disconnect battery for 30min or so to clear out gremlins if any and see if the communication is reestablished.
Best advice from me would be:
Take the RX to some one who knows how the A/C communication works and let them diagnose the problem.
Salim
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