RAM 1500 Van V8-5.9L VIN Z (1998)
Evaporator Core: Description and Operation
Combination Coil
SYSTEM OPERATION
Models equipped with the optional rear heater-A/C unit have a combination coil located within the rear unit housing. It is called a combination coil
because it combines the functions of a heater core and an evaporator coil into a single heat exchanger unit.
The combination coil features six rows of tube and fin construction. The two rows located toward the outboard side of the vehicle serve as the
heater core and have engine coolant circulated through them whenever the rear water valve is open. The four rows toward the inboard side of the
vehicle serve as the evaporator and have refrigerant circulated through them whenever the air conditioning compressor is operating. The amount of
refrigerant flowing through the combination coil is controlled by a dedicated rear thermal expansion valve.
The combination coil can be accessed for service by removing the rear heater-A/C unit upper housing. The combination coil cannot be repaired
and, if faulty or damaged, it must be replaced.
