Join Date: Jan 2010
Location: Fountain Valley California
I do know that the fans will not turn on right away. The A/C system high side pressure has to increase up to something like 290 psi before they are commanded to turn on. Maybe your compressor is a little slow to ramp up towards its max output in a timely manner (at times). That would delay the rise of the pressure needed to request the fans to turn on.
An if the A/C high pressure line stayed just below the threshold psi for turning on the fans, I think the A/C would still be supplying you with some cool to fairly cold air, as long as the car was moving along at a nice pace (not so much sitting still).