Dieselsite Max AC Assist

WORKS ON ALL 1994 - 2008 F250-F450 Gas Engines as well. In 1994-2008 HD and Superduty trucks, hot engine coolant is flowing through the heater core whenever the heat or Air Conditioning is turned on. The system does not differentiate between the two. This is fine when you are running your heater. However, running the Air Conditioner is a different story. When your AC is on, your cold air is not only flowing across the evaporator coil but it also flows past the heater coil which has hot engine coolant flowing through it. Even with the air flow diverted around the heater core, the heater is still emitting heat just like a radiator. This results in a very inefficient air conditioning system in these vehicles.