Toyota Repair: Climate Control for 1999 4Runner Ltd Not Working Properly, toyota 4runner, salvage yard

Question
I've got a 1999 Toyota 4Runner Ltd with Auto Climate Control.  A few months ago I noticed that I could only get cold air when I set the temp setting to "COLD." Anything else, 66 degrees - "HOT" caused hot air to blow (i.e.- a setting of 72 degrees blew hot air).  Seems to me like the air isn't mixing properly.  Is this something I can fix on my own.  The dealership wants upwards of $1000 to swap out the climate control panel and possibly other work.  Is there an easier fix? Any chance I can buy a used climate control panel and use that? Thanks for your help.

Answer
The auto a/c system is pretty complicated and I would recommend having the dealer diagnose and repair it, I have no quick solution, it may be the control panel or it may be one of the servomotors or even a wiring problem, you may be able to locate a used control panel at a salvage yard and take a chance that it may solve the problem.