Chrysler Repair: heater & air vent bad smell, spring clamp, air vent

Question
We have a 1996 town&country with leather interior we live in the south very humid and hot here lately when we turn on the air or heat theirs a real, I mean real bad smell out of then dash vents like rotten cow it'll go away after 30 min any ideas this'll make ya sick we do smoke in the car but thats not it. Thank

Answer
Hi Phil,
There is probably mold growing in the bottom of the heater/AC housing due to a failure to drain away the condensation that occurs when humid air flows across the refrigerant coils as the AC is operated. There is a collection pan inside the unit at the bottom of the housing and there is a drain nipple that projects thru the dash body panel (also called the firewall) to the external surface at about the level of the floor. The nipple has a rubber tip with a bend in it so that the fluid will drain  but is still protected from mud hitting the opening and blocking it. The rubber tip is held in place by a simple spring clamp. To find the tip and the nipple you need to raise the passenger side front of the van and get under it and look for this drain outlet on the passenger side of the dash panel/firewall. Once you find it, squeeze the clamp to remove the rubber tip and then you may find that either the lumen of the tip is blocked with debris or the lumen of the nipple itself is blocked. Use a stiff wire to clean out the lumen to make sure there is no further obstruction of the drain out function. (Be careful not to let the stale water that may be filling the pan drain on you).
I believe there may some sort of deoderant/fungicide that you can spray into the air intake at the external base of the windshield (with the heater blower running), but I have not used such a product nor would I want to breathe the compound.
But once you get the drain open the source of the problem will be cured and the smell should dissipate over time. You should normally see water puddling under the van directly under the rubber tip after you park the van, within an hour after using the AC. That is a good sign that the condensate is draining from the pan. When you don't see it that is a sign that the obstruction is back. I believe things should improve gradually once you remove the condensate water build up in the housing. Unfortunately the removal of the housing unit is a big job so there is no simple way to clean out the interior of it. But see if you can find some sort of safe and effective spray to encourage the deodoration process.
Roland