"Yup summer has arrived and I find I can't turn the heat/temp control
all the way off.  Lever fully over and I still get warmed air through
the vents. Any hints on what I have to do to fix this."
Thanks Don

I first tried adjusting the cable mechanism just behind the dash, where the
sliding control is, to be sure the "closed" position was completely closed.
That didn't do it so I replaced the valve, up above the spare under the
front of the van. That did it. A messy job and good excuse to change the
coolant completely. I got the valve from Bus Depot, I think.
http://www.busdepot.com/busdepot/details.jsp?partnumber=171819809E

Bob