Why won't my Audi A4 S-Line's heater produce warm air?

I have an Audi A4 S-Line on a 55 plate. The heater is now blowing out cool air. Can you help? I've had the air conditioning on most of the summer.

Asked on 24 August 2010 by audi s line

Answered by Honest John
Could be a lot of things. Blocked heater matrix, stuck flap, failed control, and if it has climate control a failed cabin thermostat.
Tags: air con
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