Mercedes Benz repair: w126 a/c, blower motor resistor, climate control unit

Question
I've got a '85 380SE with 107,000 mi., it's been a great car but this summer I've had a/c problem if the car has already been run/engine warm and you turn on the a/c it blows hot.  if you turn it off and on you can get it to work but it takes 10-15 minutes to cool down once this happens it works fine. if you get the car cooled down and turn off the car then start it back up it will blow hot again and you have to monkey with the switch on/off and wait again for it to cool down.  do you have any ideas on what it might be?  

Answer
You may have a low charge due to a very small leak; however, if it is electrical the following links may help diagnose or repair your problem:
http://boostnbenz.1baddsm.com/DIY/Climate/
http://www.mercedesshop.com/Wikka/AcDiags

Here are the parts most likely to cause your problem:

A/C Sampler Blower Motor
A/C Blower Motor
A/C E.T.R. Switch = Evaporator Temperature Regulation Switch.
A/C Evap Temp Sensor
A/C Lock-Out Sensor
A/C Pressure Switch
A/C Temp. Switch...
Blower Motor Resistor
Blower Regulator...
Blower Regulator Switch
Climate Control Unit
Aux. Fan Resistor
Auxiliary Fan Assembly
Auxiliary Fan Screen
Auxiliary Fan Switch

I suggest you join http://www.mercedesshop.com/shopforum/forumdisplay.php3?f=1

if you plan to DIY repair.