The Chief has a 2006 F-250 6.0 Lariat with the auto control HVAC system. The truck AC doesn't work very well setting still. It cools better at highway speeds. Obviously there is an airflow problem.
The pressures on both high and low sides are high with the truck setting in the shop. The outside temps lately here have been around 100F with 90% humdiity. The condensor is clean and I can shine a flashlight through the codensor anywhere. I double checked the factory charge and it is correct. The truck does have a tube style grille in it. I can put a shop fan in front of the truck setting and it helps.
My question is: Is the engine fan controlled through the PCM by a high pressure switch? Is there, perhaps, a software upgrade I can have done at the dealer? Any other ideas?