Remove the black plastic outside vents at each upper rear corner of the sides of the van.  Inside you should find rubber hoses with valves on the ends.  Usually, the valves get plugged with debris and the water backs up and overruns the condensation trays inside the van and it rains.  Clean out the valves and you should be good to go for another 20 years. 

Tom

-----Original Message-----
From: David Bjorkman <ddbjorkman@VERIZON.NET>
To: vanagon <vanagon@GERRY.VANAGON.COM>
Sent: Tue, Jun 17, 2014 6:16 pm
Subject: [VANAGON] Raining inside

Hi All;

On a recent trip my wife noticed that it was raining inside the bus while the 
A/C was running.  Apparently I need to clean out the drains.  Would someone 
please point me to a good work up or two on doing this job?  A video might be 
nice also.  I have heard that it is a lot of fun and a quick job(yeah, right, 
like that happens).  All kidding aside, I would like to know of any spots where 
the Bentley may be vague, or of interesting (read easy) ways to support the 
cabinet, which I believe needs to drop somewhat to do this job.
Any help appreciated.

Dave B.