A6 heating problems

[Tm Gordon]

Hi I've had an Audi A6 3 litre diesel for 3 years with various problems 

Now I have no hot air on the driver's side but if I turn the heat down to cold on the passenger side then I have heat on the driver's side can anyone please help 

[Steve Q]

Have you had the heater matrix checked? 

Is the car engine temperature staying consistently at 90 degrees? 

[Tm Gordon]

Haven't had the heater matrix checked 

Car temperature is fine had 2 diagnostics one said not sure the other one said matrix dash out and 1,000 but he couldn't guarantee it was the matrix 

Audi want 165.00 for an hour but again can't guarantee it will be done in an hour may need further investigation