I have exactly the same issue with my 2012 Limited (JBL system w/o Nav). Touching the Volume knob will produce unexpected results. Volume will randomly go up or down just from touching it. Turning the knob either direction does not result in a normal linear volume up/down result. The Volume buttons on the steering wheel still work perfectly, so I have had to get used to just adjusting the volume there instead of on the radio itself.

Sorry I don't have a solution for you but apparently it is a common failure point on the radio system.

 

Very common issue, Pretty easy to fix too.
Just get some CRC contact cleaner, remove the vol knob, just pull it straight off.

Make sure the radio is off and that the vehicle is off!!

Then you will see the shaft has an outer shaft that does not turn and an inner shaft that does turn.
Try to shoot a bunch of CRC cleaner down the shaft between the inner and outer shaft.
Then Keep turning the heck out of the inner shaft back and forth and all around many rotations in each direction.
Let it dry for a moment and repeat 2 or 3 times.
Then replace knob and enjoy for another year or two

Total procedure should take less than 2 or 3 mins total from start to finish.

 

This, or you could even do the same procedure without the contact cleaner (just spin the knob round and round like you're a 2-year-old for a couple of minutes) like I did and still get good results.

 

@tbm5690
Yeah tried that ! It just goes anywhere, up or down. No control whatsoever ! I’ll try the contact cleaner and see if I get better results. Thanx anyways.

 

Thanks for the great tips. Just fixed the volume control on my 2009 Highlander. Easy as pie.

 

Rotary radio volume knob not working right? Mine does not do anything when I turn it at a normal speed. (I tried spraying contact cleaner but that had no effect ) But it does work if I: 1.) Turn it slowly - AND importantly - without stopping. 2.) Give it at least 1/2 of a turn before it 'grabs'. It might get too loud. If so, don't let go of the knob - just turn it back down. Another tip: when you turn it down, it will likely be too low - until you master the speeds. So, just try rocking it back and forth until you get it right. Or maybe have a shop repair the knob.

 

Thank you! I have two HL with this problem and I just fixed them both!

 

I tried the CRC route... it sorta helped... but now I have an issue as I turn the volume it randomly turns off and on the radio and the push to turn on and off the radio no longer works. The knob won't push in.

 

What kind of CRC did you spray? CRC makes a wide variety of solvents/cleaners. Sounds like it was not contact cleaner and may have melted the plastic parts of your volume knob.