draining coolant

[steveb@cme.nist.gov]

This is probably in the archives somewhere...

My Haynes manual doesn't have a word about the automatic climate control
system on my '85 5000S.  So, how do I set the heater valve wide open
on my automatic climate control system (which apparently needs a new
programmer too) so that I can get a complete coolant drain/flush?

I need to do this tomorrow and I'm on the digest, so please copy me
directly on your response even if you reply to the list.  Thanks a ton,

Steve