Bulb out icon on but all are working?

[Gigi64]

I recently put my Audi A3 TDI in to a garage as I had no heating, it was just blowing cold air. This had happened after I had the air con topped up. They had the car for 4 days, and when I got it back they said that I had some heat but to keep the fans on low as it wasn’t completely fixed (next move would have been to replace the heater matrix which would have been £££££’s). I wasn’t overly happy, as actually only occasionally it blows out warm and this cools down after about 10 minutes of driving. Also, when I drove it away it had the bulb out light on. They said it would probably right itself 🤷🏻‍♀️ but it obviously didn’t. So I took it back. They did 2 different diagnostics tests on the car and found nothing. All the bulbs are working fine but the light is still on. They mentioned that it may be corrosion, but it just seems very suss that it goes in ok and comes out not. Any ideas please? 

[Magnet]

Hello Gina,

Welcome and thanks for joining. 
The brake lights sometimes have two bulbs in them . One can fail, but you still have a brake light. 
Test would be to get an assistant to press the brake pedal when it’s dark while you assess the light intensity on both rear lights. 
Let us know how you get on.

Kind regards,

Gareth. 

[Gigi64]

Many thanks for the info Gareth. Unfortunately we tested the brake lights at night and both were of the same brightness 🥴