Chrysler Repair: 2000 dodge caravan a/c:mold odor in cabin, dodge caravan, road dirt

Question
The A/C in my 2000 Dodge Caravan works fine but there is a terrible smell when the A/C is turned on.  I have been told that the evaporator coils need to be cleaned. How do i do this and does the dashboard need to be removed to do this?

Answer
Hi Wayne,
I am not certain about the various approaches to remediating a pre-existing odor problem in the AC system. It is generally the case that its cause is that the condensation of moisture on the evaporator coils is not being successfully drained away from the cabin. There is a tray below the coils that catches the condensate and that tray has a drain pipe that is routed through a hole in the firewall at about floor-level and about midline on the body. If you look under the van at the firewall/floor area you should find the rubber hose with perhaps a flap that is supposed to help keep road dirt that is kicked up from clogging it. But once you find it, open up the flap and stick a stiff wire into the lumen of the drain hose and poke around to free-up the passageway. Be aware it may start draining the putrid water so don't be underneath it!
Once you have the drain working again, the odor may over the course of time diminish to negligible as the mold dies for lack of continuing moisture. There may well be some chemicals that you can spray into the air intake that will kill the mold, or some other such 'strategy in a bottle' that is short of any dismantling which you would want to avoid as that is very cumbersome and likely to cause other functional problems to actually get to the evaporator. So that would be my advice as to how to begin.
Roland