Get yourself some anti-bacterial surface spray - Febreze or Dettol would do it - find the air intake and give it a blast....
I think the trick with aircon (some might disagree, but it's been my experience over many years) is to leave it on all the time at, obviously, a temperature that suits on a low fan setting. That way it won't build up the spores that are causing the aroma.
You might find some 'dedicated' A/C cleaner spray rather than the products suggested by the way. I'm sure Lexus or Jaguar would have such a thing.
Hope this helps.
N