Cooling System: Description and Operation

CONTINENTAL & MARK VII W/6-146 DIESEL ENGINE
These vehicles have an electric pusher fan mounted behind the grille, in addition to the belt driven engine cooling fan attached to the water pump. The electric cooling fan system consists of a fan and an electric motor mounted on the fan shroud, an ambient temperature switch and a cooling fan relay.
The electric cooling fan is wired to operate only when the A/C compressor is operating and the ambient temperature is above 70°F. The cooling fan relay is energized by power from the A/C blower motor speed controller which then allows battery current to flow to the electric cooling fan. The cooling fan relay is energized only when the A/C compressor clutch field coil is engaged and the ambient temperature switch, located on the hood lock support, is closed. The electric cooling fan will only operate when the ignition switch is in the ``Run'' position, since the A/C system can only operate when the ignition switch is in ``Run''.
The A/C clutch field coil is powered through the A/C cutout relay, which is energized to turn off power to the clutch field coil in one of two ways. With EGR vacuum below 7 inches Hg and turbo boost pressure below 2 psi the A/C cutout switch and the A/C turbo boost switch are closed, providing a ground to energize the A/C cutout relay. With the relay energized, the current to the A/C clutch field coil is turned off.
With engine coolant temperature above 233°F, the coolant temperature switch closes, providing the ground to energize the A/C cutout relay.