Weak AC, and a solution (HVAC reset via MUTE)

[Dave Rosenthal]

Well, I figured I would just leave a trail here for posterity. My Grenadier has been having an issue for a few weeks where even though it's a warm day, and it's very hot in the cabin, the auto mode barely blows the AC. If I do turn the temp control all the way to "LO" then, and only then, do the fans ramp and I get lots of cold air. If I turn it up one click--to 66F--the fan goes to super low speed and even though a bit of cool air is trickling out the vents, the interior is overheating.

So, I knew the system was physically working, and that it was some control problem. I tried a bunch of the tricks people mention about knob position, turning the car on slowly, etc. Nothing.

But, a simple 30sec press on the mute button (while the car was running) rebooted the infotainment controls and instantly the fans spooled up and the system is working again. I hadn't seen this mute trick mentioned except in one post by @Skydance so, thanks Skydance!

 

[TheDocAUS]

A complete reboot of the Head unit is also possible (not just HVAC).

Rok Dr Guide

Post in thread 'Grenny infotainment craps the bed'

Jul 29, 2024

Reset/reboot the headunit (aka Console screen).

Hold the Mute button (located at the centre bottom on the vertical panel) in until half the Console screen goes blank (do not release the button). Continue to hold the Mute button in until the whole screen goes blank. Only then release the Mute button. That will reset/reboot the headunit.

Then reconnect the phone.

See if that helps.

• TheDocAUS

• 

 

[Dave Rosenthal]

Thanks for the info. I did the full reboot.

 

[HereinDaRockies]

so are you saying, the HVAC was working poorly consistently, across many driving sessions. Then you rebooted the infotainment system. Now it's all good across multiple drives?

 

[TheDocAUS]

Thanks for the info. I did the full reboot.

Let us know if it helped.

 

[Lazaring]

Then, does the reboot fix the problems with the HVAC?

 

[HeavyFoot]

Someone here pointed once that the exterior temperature is incorrect when the system isn’t functioning properly. I’ve found that to also be the case twice. I hypothesize the system is more complicated than it needs to be and is figuring outside temperature to blend with appropriate system temperature to reach desired results. A simple reset resulted in immediate properly functioning HVAC system twice. Perhaps the root of the issue is the exterior temperature sensor.

 

[landmannnn]

Someone here pointed once that the exterior temperature is incorrect when the system isn’t functioning properly. I’ve found that to also be the case twice. I hypothesize the system is more complicated than it needs to be and is figuring outside temperature to blend with appropriate system temperature to reach desired results. A simple reset resulted in immediate properly functioning HVAC system twice. Perhaps the root of the issue is the exterior temperature sensor.

Actually the root cause is that the whole system is based on a X5.
A Google search will reveal X5 owners with exactly the same issues.