Cooling fans – circuit operation

COOLING FANS – CIRCUIT OPERATION

Condenser Fan Operation (300Tdi)

The Condenser Fan Motors (M113, M121) on vehicles equipped with diesel engines operate when any one of the following conditions occur: 1. Coolant temperature exceeds 100
C (212
F). 2. The A/C is operating.

Condenser Fan with High Coolant Temperature Operation (300Tdi)

When the Ignition Switch (X134) is in position II, battery voltage is applied to the Ignition Load Relay (K127). The relay is energised, applying battery voltage to the Condenser Fan Relay (K109). If the coolant temperature exceeds 100
C (212
F), the Condenser Fan Coolant Temperature Switch (X113) closes and energises the Condenser Fan Relay (K109) by applying ground to the relay’s coil. When the relay is energised, voltage from fuse F3 is applied to the Condenser Fan Motors (M113, M121) through the relay’s contacts.

Fan Operation with A/C (300Tdi)

With the Ignition Switch (X134) in position II, battery voltage is applied to the Ignition Load Relay (K127). The relay is energised, applying battery voltage to the Condenser Fan Relay (K109) when the Front A/C Switch (X225) is turned on and the Front Fan Speed Switch (X247) is turned to positions I, II, III, or IV and grounding terminal 86 of the Condenser Fan Relay (K109). The relay energises, applying battery voltage from fuse F3 to the Condenser Fan Motors (M113, M121).