Was just undedr the wife's car this week and did notice the condensate drain nipple. Looking up from the bottom, it was centered just below a pair of hoses that enter the firewall near the base, just slightly on the passenger side of center.
I'd suspect one of two things: Either the clutch is slipping as it gets warm as Ray suggested, or the evaporator is freezing up.
You can perform a visual inspection on the clutch by watching it engage or disengage during A/C operation. Easy to see from underneath. Hard to see from the top, but is possible. If this were an SHO, I'd suggest reshimming the clutch gap as that is a common problem on that car. Don't know if it's applicable on the 'Tour, though.
If the evaporator freezes up, you would notice a damp or moist condition of the air coming from the vents. If the car were then parked, it would leave a very large puddle of water as the ice melted - assuming the drain is open.
A clogged drain will often cause foul odors, but the most common symptoms will be either wet carpet or the sound of water sloshing around inside the dash (A/C Evap plenum).
Steve
