Cold air to footwell and back passenger vents A4 B9

[Vytas]

Hello everyone,

Looking for help if someone had an issue like this:

I only get cold air to the rear passenger vents and footwell on my 3-way climate control. I get warm air to the front vents and windshield at ~22 Celsius when it is set to high. However when I only set the blower to blow to the footwell area then I don't get warm air ~19 Celsius no warm air to the back at all. Has anyone had a similar problem and got it fixed? Garge checked the flaps were opening correctly and said they would need to look at the heater box as the problem seemed to be there, but it's a huge job with around 24 hours of labor and they couldn`t guarantee it would be fixed. I am thinking of trying to change the heater core matrix and flushing coolant. Thank you and appreciate your help!

Edited November 21 by Vytas