T27 Heater/Aircon control malfunction

[Leex2017]

We have 2011 and 2014 diesel avensis. Both have Dual climate control. The 2011 model heater/aircon control has started malfunctioning recently.

Basically passenger side works fine running from Lo to Hi temp when controlled individually. Drivers side only goes from Lo to about 16 and can fluctuate randomly when temp knob is used.

I tried a Battery disconnect-no joy. Anybody see this before? Guessing replacing unit may be the solution.

[HartmannX]

It is the knop/potmeter replace whit a new panel or used

Sendt fra min SM-G920F med Tapatalk

[Konrad C]

There is a self diagnostic system that I tried on my car - http://www.cardiagnostics.be/-now/Self Diagnose Toyota Corolla ECC-panel.htm

 Give it a go.

[Leex2017]

Thanks for that link Konrad. The diagnostics appear to work similarly on the Avensis also but it is reporting a 00 error. The error codes seem to reference issues outside of the control unit. I think my issue is with the actual driver side temperature knob on the control unit.

I will need to remove the unit to get the part number. I see several units listed on eBay but all have different trim colour/finish to my unit (textured silver/bronze). Wondering worst case, if the unit trim can be swapped? I'll know better when I remove the unit.

[xzirri]

Which model is it? I usually use this page to find the correct part numbers.

[Leex2017]

The issue miraculously disappeared in the past week. 

I had some trim removal tools just purchased and researched on here how to remove the radio etc.

Similar experience previously with remote central locking not working for a few months and fixed itself again. 

[2020AM]

Hi, 

I have the same issue passenger side air con controller works fine running from Lo to Hi temp when controlled individually. Drivers side only goes from Lo to about 18 and can fluctuate randomly when temp knob is used. Did a diagnostic check and the code comes up as 00.

- how easy is it to remove the current air con controller and replace with another one - can anyone kindly help to provide some guidance?

[2020AM]

Can someone kindly help me with my below query please?

'how easy is it to remove the current air con controller and replace with another one - can anyone kindly help to provide some guidance?'

This is for 2011 Toyota Avensis Estate 2.2 diesel D4D 150bhp version. Thanks.

[Konrad C]

 

https://www.toyotaownersclub.com/profile/76861-konrad-c/content/?type=forums_topic_post

[2020AM]

Thank you so much Konrad. The photos are very useful. Will try to give it a go 🙂

[yossarian247]

7 hours ago, 2020AM said:

Thank you so much Konrad. The photos are very useful. Will try to give it a go 🙂

It might be worth trying my trick first. Switch the ignition off, then spin the temp control knob repeatedly back and forth really fast with your finger a few times. I had the problem with the temperature control behaving oddly last year, and simply spinning the temp knob seems to have cleared whatever dirt was on the contacts. It has worked fine ever since.

[2020AM]

Thanks Nick. I'll try as you suggested first - Much appreciate. 🙂

[2020AM]

Tried your suggestion and it worked. The temp controls moves from Lo all the way to High. Thanks Nick!

[yossarian247]

19 hours ago, 2020AM said:

Tried your suggestion and it worked. The temp controls moves from Lo all the way to High. Thanks Nick!

Fantastic! Really please it helped.

[rob42]

On 1/5/2021 at 8:57 AM, yossarian247 said:

It might be worth trying my trick first. Switch the ignition off, then spin the temp control knob repeatedly back and forth really fast with your finger a few times. I had the problem with the temperature control behaving oddly last year, and simply spinning the temp knob seems to have cleared whatever dirt was on the contacts. It has worked fine ever since.

I had the exact same issue and your trick work perfectly. Thanks 

[Catlover]

On 9/7/2017 at 1:30 PM, HartmannX said:

It is the knop/potmeter replace whit a new panel or used

Sendt fra min SM-G920F med Tapatalk
 

I think Morten got it right.  Spinning the knob around will clean muck away, permanent solution is to replace what’s behind the knob.

[yossarian247]

1 hour ago, Catlover said:

I think Morten got it right.  Spinning the knob around will clean muck away, permanent solution is to replace what’s behind the knob.

Perhaps, but I'm not sure there is a permanent solution as such. Considering how common this appears to be with the T27 Avensis temperature control won't the replacement just do the same in a few years anyway?

Konrad's method of dismantling and cleaning the contacts properly is worth trying, as I think it is just dirt that causes this.

 

[Cessna]

Has anyone tried a short blast with one of those aerosol electronic contact cleaners? I'm not suggesting anybody tries it just in case something gets fried (although with the ignition off it should be ok). But it would be interesting to know if somebody has already tried it - so I can have the solution ready for if mine starts malfunctioning!

[Heidfirst]

3 hours ago, yossarian247 said:

Considering how common this appears to be with the T27 Avensis temperature control

Bearing in mind that they sold 100,000s of these (& I am sure that the components are shared with other models) & there appear to be relatively few complaints it's not common at all. 😉 

[Catlover]

3 hours ago, yossarian247 said:

Perhaps, but I'm not sure there is a permanent solution as such. Considering how common this appears to be with the T27 Avensis temperature control won't the replacement just do the same in a few years anyway?

Konrad's method of dismantling and cleaning the contacts properly is worth trying, as I think it is just dirt that causes this.

 

It is a wearable component.  Computers with hard drives were the same, anything moving wears, a spinning disc wears. In the case of a computer a Solid State Drive SSD made the problem more durable.

[yossarian247]

10 minutes ago, Heidfirst said:

Bearing in mind that they sold 100,000s of these (& I am sure that the components are shared with other models) & there appear to be relatively few complaints it's not common at all. 😉 

I have known this type of control fail in the same way on other makes of car too though, so it does appear to be a weakness of the design. Not necesarily just heater controls, we had an Astra G where the radio volume control was this same type of 'clicky' control knob and when turning it the volume level in the display would jump up and down randomly, in just the same way the temperature level does in the Avensis.

[Fortytwa]

On 1/5/2021 at 8:57 AM, yossarian247 said:

It might be worth trying my trick first. Switch the ignition off, then spin the temp control knob repeatedly back and forth really fast with your finger a few times. I had the problem with the temperature control behaving oddly last year, and simply spinning the temp knob seems to have cleared whatever dirt was on the contacts. It has worked fine ever since.

So pleased I looked on here, this actually worked. I don’t know how long it’ll last but it’s certainly cheaper than the £6-800 that Toyota quoted when I mentioned it to them. 
Thank you for the tip. 

[yossarian247]

3 minutes ago, Fortytwa said:

So pleased I looked on here, this actually worked. I don’t know how long it’ll last but it’s certainly cheaper than the £6-800 that Toyota quoted when I mentioned it to them. 
Thank you for the tip. 

It did eventually get worse on my car, however as the car had been serviced at a Toyota dealer it was covered by the 'Relax' warranty so I got the entire control unit replaced at Toyota's expense.

[Konrad C]

To this day, the heater control fix I did years back is still working well. 

 

[Cyker]

5 hours ago, yossarian247 said:

It did eventually get worse on my car, however as the car had been serviced at a Toyota dealer it was covered by the 'Relax' warranty so I got the entire control unit replaced at Toyota's expense.

Niiice  

We can add another person to the Successfully Relaxed tally