Geoff-R

Just a thought that part may be component protected so replacement isn't a simple case of swap out/in. 

5 minutes ago, simon_m29 said:

Further to my post above, my A3 has now been into 2 local garages. The first said they couldn’t find any reason for the faults. The second said it’s probably the heater control on the dashboard. I’ve sourced a new part and am trying to take out the old part and slide in the new one! Nightmare! Does anyone know how I remove it? There doesn’t appear any way of loosening the clips. 

Are there any obvious clips on the new part? Sorry don't know how to fit it but if it doesn't screw in behind the dash I'd assume there is a release clip. I'm sure someone else will be along to advise. 

Let me know how you get on still no heaters either and the weather is getting colder!

On 10/23/2019 at 6:32 PM, dan1991 said:

Hi all,

Having the same issue with my Audi A3 2.0 TDI 2014.

About 3 weeks ago my heaters stopped working, nightmare driving in the rain as the windows steamed upo so much! The only way to remedy this is to use the air con on the windscreen - yes its freezing and not the time of year to be sat in an air conditioned car first thing in the morning.
Anyway, i noticed my coolant has turned a very slightly darker (muddier) shade of pink but i didnt think it was that major but might have soimething to do with why my heaters have stopped blowing hot air. While getting my car serviced i asked the garage to take a look (very good guys, honest and fair) and see if they can find out what has gone wrong. 
Turns out my heater matrix is blocked solid, they attached a jet wash to the inlet to try and flush it and it was seized completely - most likely because i added inferior coolant over the past 2 years ive owned the car.
The garage advised me to put a coolant flush into the system to see if that will eat away at the blockage. I just went to halfords and bought a simple coolant flush from Holtz then gave it to the garage to use. They said i can drive it but to avoid long journeys for now, ill give it a few days of the flush working through the system and maybe, just maybe, it will clear and i can finally feel warmth again!

I will post results on the weekend but i fully expect to have the matrix replaced, they told me to do this the dash will have to be replaced and it will be a pig of a job but it needs to be done.

I didnt expect the heater matrix to seize up this quick, its only 5 years old but i would reccomend buying proper coolant and not use the cheapest available like i did. I know i am stupid in this respect, maybe others can learn from my mistake lol

Cheers
 

How have you got on Dan?  Got exactly the same problem on mine and the garage recommended exactly the same remedy.  Has flushing it worked?