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Hyundai Wiring Diagram Radiator Fans

Hyundai wiring diagram for radiator cooling fans

This is  a typical Hyundai wiring diagram for the radiator fan and AC condenser fan. The system uses a radiator fan relay and a condenser fan relay. Both receive power from fusible links, not ordinary fuses.

How Hyundai radiator fans work

The control coil for the radiator fan relay and condenser fan relay receive power from the engine control relay that is activated when you start the vehicle. The ECM monitors engine temperature through the engine coolant temp sensor. When it senses that engine coolant temp has reached a point where it needs cooling, the ECM provides ground to the radiator fan relay control coil. The relay activates and provides power to the radiator fan.

The AC condenser fan relay is activated by the ECM when the AC switch is turned on. The ECM then provides ground to the control coil on the condenser fan relay. The condenser fan relay provides power to the condenser fan. Both fans ground receive ground at G109 located on the right radiator support.

Hyundai overheats

If the radiator fan relay is activated and the ECM detects that the fan can’t provide adequate cooling, it will activate the condenser fan relay to provide supplemental cooling. If both fan can’t provide enough cooling and the temperature gauge rises into the danger zone, stop driving the vehicle and have it towed to a shop. Continuing to drive while the engine is overheated can warp the cylinder head and damage the head gasket, costing at least $1,500 in repairs.

Check fan operation first

If the gauge indicates an overheating condition and both fans are running

Check for plugged fins on the condenser and radiator

Check coolant level

Check water pump operation

Check for a damaged head gasket

Troubleshoot Hyundai overheating condition caused by fans

Check the fusible links

Remove the Engine control relay, radiator fan relay

fusible link, hyundai overheats

Fusible link

and condenser fan relays and check for battery voltage. The relays are located in the engine compartment relay/fuse box. Check for battery power in the relay sockets on these terminals. These pins should have power at all times, even with the key out of the ignition.

Engine control relay: pins 2 & 5

Radiator fan relay: pin 1

Condenser fan relay: pin 2

If you find power at all those points, that confirms the fusible links are good.

Check for relay control power

Next, turn the key to the RUN position and check for battery voltage on these pins:

Radiator fan relay: pin 5

Condenser fan relay: pin 5

If you see battery voltage, that confirms the engine control relay is providing power to the control coil side of the relays.

Check for condenser fan control coil ground

With the key in RUN position, turn the AC ON. Then check for ground on pin 1 in the condenser fan relay socket. If you detect good ground, the ECM is operating properly

Check radiator fan operation

If you’ve confirmed the fusible links are good radiator fansproceed by placing the relays back in their sockets, run the engine at idle and wait for the radiator fan to activate while watching the temperature gauge. If the gauge rises into the danger zone but the radiator fan doesn’t activate, remove the radiator fan relay and check for ground on pin 3. If you don’t get ground on pin 3, the ECM is not activating the radiator relay. That can be caused by a faulty engine coolant temperature sensor or a wiring problem between the ECM and pin 3.

If you do find ground on pin 3, jumper across pins 1 & 2 in the socket. If the radiator fan runs, then the radiator fan relay is bad. Replace it.

If the fan still doesn’t run, provide battery power and ground directly to the fan. If it doesn’t run, the radiator fan is bad

Check condenser fan relay operation

If you’ve already confirmed that the condenser fan relay fusible link is good and is receiving control coil ground from the ECM when the AC is turned on, but the condenser fan doesn’t run, jumper across pins 1 & 2 in the condenser fan relay socket. If the condenser fan runs, the relay is bad. Replace it.

If the condenser fan doesn’t run, provide battery power and ground directly to the fan. If it doesn’t run, the condenser fan is bad.

If both fans run but the engine overheats

©, 2017 Rick Muscoplat

Posted on by Rick Muscoplat


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