Volvo Repair: AC compressor wont turn off, ac compressor, junk car

Question
QUESTION: Hi again
I replaced the thermostat and the relay (from a junk car),
the ac works great, how ever it will not quit (I can look and see the ac clutch)when I turn the thermostat off.
Thank you again for your lighting response.
Tony
ANSWER: Tony, Thermostat?  I dont remember what I told you.  Please refresh my memory.  Roger

---------- FOLLOW-UP ----------

QUESTION: Sorry, I meant..."AC RHEOSTAT". I did replace the relay per your suggestion and the AC works great.... It just can't be turned off with the "Rheostat".
Thank you again  

Answer
Tony, It may be a faulty switch.  Is it turned all the way off?  You may have miswired it.  I have seen that happen. Those double green wires go in a specific order as well as the white red wire.  Which system do you have?  Accumulator or reciever/dryer?  Roger