When our daughter was born I became concerned that that I was either
freezing her or cooking her in the back of the camper.  I added a line
thermostat model 4E036 less than $20.00, that I bought through Grainger, to
control the blower.  I interrupted the ground to the blower motor using
standard 1/4 spade connectors, this way all three speeds are controlled, and
it's easily returned to it's original setup.  I just set the temp on
the stat, set the blower speed on the dash and I don't have to worry. It
cycles on and off just like home.  I mounted the thermostat next to the
"clothes closet" with velcro, so I can remove it easily during the summer.
There are other thermostats that could be used, I just picked the least
expensive.  Hope this helps someone.  Good luck.

Doug
'86 GL Westy
Maryland