Volvo: AIR CONDITION S 70 VOLVO, exact problem, expansion valve

Question
MY AIR CONDITIONER WAS CHECKED TWICE FOR LEAKS.
THE EVAPORATOR CORE WAS REPLACED IN
SEPTEMBER,2005. NOW THE AC WILL  BLOW WARM AIR
INTERMITTENTLY.  IT USUALLY HAPPENS WHEN I HAVE
BEEN STUCK IN TRAFFIC OR STOPPING AT LIGHTS
FREQUENTLY.  IT USED TO GO ON IMMEDIATLEY WHEN
I HIT THE HIGHWAY, BUT EVEN THAT IS BECOMING A
PROBLEM. I SMELL A HUMID OR RADIATOR SMELL AND
THEN THE WARM AIR STARTS.  IF I PULL OVER AND RESTART
THE CAR, THE AC SEEMS JUST FINE. I HAVE A GREAT
SERVICE TEAM BUT THEY CANNOT FIND THE SOURCE OF
THE PROBLEM.  I JUST READ ABOUT AN EXACT PROBLEM
WITH AN S70 ON LINE.  CAN YOU HELP? THANK YOU SO
MUCH.  

Answer
maybe the electric fan , the a/c system has it's own radiator (very front of car) to get rid of heat, so fans have to work in traffic....they are set to come on when coolant gets to a certain temp. or they come on more often with a/c, the computer controls the fan (the computer knows the vehicle speed and whether a/c is on)check fuses for it, it's a complicated problem, maybe a bad pressure switch, expansion valve, bad clutch on a/c compressor? (could be any one of these things, sounds like your team doesn't know how to troubleshoot that well