Air Vent Control Knob sticking

[Crunchie]

Hi, my 2013 1.3 vvi Yaris has a recurring problem with the air vent selector knob on the dashboard. It is very hard to turn and requires excessive force, but it will go to all positions. It has been to the dealers twice to rectify, both times without success (Typical main dealer....no proper mechanics to fix problems) Anyway, first time, the car was in for 6 hours and all they done was to lubricate the control cable. Car was handed back but the fault was still there. I immediately booked the car in for a week later for 2 days. This time the entire control panel was replaced. This solved the issue for a couple of weeks but it has returned.
Is this a common issue with the Yaris and is there an easy DIY fix or is it a complete dashboard out job? Really don't want to use main dealers as I have always, without exception, had problems when I needed to use main dealers for repairs.

[FROSTYBALLS]

They may initially have had the car for six hours, but depending what other work they had booked in,  the time spent on your Yaris was probably far less. The same would probably apply to independent garages.

[Crunchie]

Only about half an hour was spent on my car. It was my wife who took it in "We'll get it done first thing" and "It'll be a quick job". She waited and watched for 5 hours before the car was driven in the workshop. Every time wifie asked what was happening the stock reply was "Your car is next, it won't be long now". Other cars came in and left in that time. Is seemed that because the dealers knew she was waiting, they were making a game out of seeing how long she would last. Nobody came out to say that they were backed up and that the wait would be a long one. Plus, nobody checked to see if the vent control problem was fixed before letting it out of the workshop. I suspect nothing at all was done to the car.

[YarisHybrid2016]

I'd find another garage!

[Crunchie]

I am going repair this control knob issue myself. Main stealers are not getting another chance as the car is now out of the lease package and I won't pay for them to play "parts darts" and charge me for the privelage. I do use a good independant garage with proper mechanics capable of repairing broken things but even so, there will be a fair old cost for disassembly / reassembly. This is why I am asking if this is a common fault with the Yaris and what fixes / procedures are necessarry to remedy the problem.

I did notice yesterday when the car was baking in the sun that the raised temp inside the cabin allowed the knob to turn easier.....not as normal but certainly easier. I suspect something within the control rod or cable or even the air gate mechanism had expanded enough to un-jam itself a little. Methinks some component needs adjusted or altered. What think you?