Theory Of Operation

WARNING: This page is about a different car, the 2016 Dodge Journey and 2015 Dodge Journey. However, it is still accessible from the selected car via links, so may be relevant.

The two speed cooling fan system uses two relays and a radiator fan resistor to control the cooling fan operation. The two relays are the High Fan Relay, Lo-Hi Fan Relay. During low speed mode, the cooling fan operates in series with the Radiator Fan Resistor, limiting the 12 Volt source the Radiator Fan Module. During high speed mode, the cooling fan motor receives a battery voltage feed directly from the High Speed Radiator Fan Relay.

During low speed mode: The PCM grounds the (N201) Fan Relay Control circuit, closing the relay to connect the Cooling Fan 12 Volt Supply circuit to the (N23) Cooling Fan Motor 1 Output circuit. The (N23) Cooling Fan Motor 1 Output circuit supplies 12 Volts to the Radiator Fan Resistor. Current flows through the resistor and out the (N24B) Rad Fan Relay Output circuit. The current is sent back to the PDC and is spliced into the (N24A) Rad Fan Relay Output circuit which goes directly to the Radiator Fan Module. The (Z904) Ground circuit provides the ground path for the Cooling Fan series circuit.

During High speed mode: The PCM grounds the (N112) Fan Relay Control circuit and the (N112) Fan Relay Control circuit, closing the High Speed Radiator Fan Relay. The Cooling Fan 12 Volt Supply circuit connects to the (N24A) Rad Fan Relay Output circuit and provides 12 Volts to Radiator Fan Module. The (Z904) Ground circuit provides the ground for Radiator Fan Module.