Replace the cooling fan relay to restore proper electric cooling fan operation on a 2016-2024 Hyundai Tucson with 2.5L I4 AWD engine.

Warnings

Tools required

Parts

• Cooling fan relay × 1 — Use OEM specification - typically part of engine relay box
• Dielectric grease × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and apply parking brake
2. Allow engine to cool completely for at least 30 minutes
3. Open hood and secure with prop rod
4. Disconnect negative battery terminal and wait 3 minutes for system discharge
5. Locate the engine compartment relay box on driver side near battery

Procedure

1. 1

   Access engine relay box
   Locate the main engine relay box positioned near the battery on the driver side of the engine compartment. Release the two locking tabs on the top of the relay box cover by pressing inward and lifting upward. Remove the cover completely and set aside in a clean location.
2. 2

   Identify cooling fan relay
   Refer to the relay diagram printed on the underside of the relay box cover or in the owner's manual. The cooling fan relay is typically labeled as 'FAN' or 'C/FAN' and is a standard 4-pin or 5-pin automotive relay. Note the relay position and orientation before removal.
3. 3

   Remove failed relay
   Grasp the cooling fan relay firmly and pull straight upward with steady, even pressure. The relay should release from its socket without excessive force. If resistance is encountered, gently rock the relay side-to-side while pulling upward. Inspect the relay terminals for signs of burning, corrosion, or heat damage.
4. 4

   Inspect relay socket
   Examine the relay socket in the fuse box for corrosion, debris, or damaged terminals. Use a flashlight to inspect inside the socket. If corrosion is present, spray electrical contact cleaner into the socket and allow to dry completely. Check for loose or bent terminals that may prevent proper relay contact.
5. 5

   Install new relay
   Apply a small amount of dielectric grease to the relay terminals if operating in harsh conditions. Orient the new relay to match the keying of the socket and the position of the original relay. Press the relay firmly into the socket until it is fully seated and flush with surrounding relays. Ensure the relay is secure and cannot be easily wiggled.
6. 6

   Reinstall relay box cover
   Position the relay box cover over the relay box, ensuring the relay diagram is visible for future reference. Press down on the cover until both locking tabs click into place. Verify the cover is fully secured by attempting to lift it gently.
7. 7

   Reconnect battery and test
   Reconnect the negative battery terminal. Start the engine and allow it to idle. Turn on the air conditioning system to maximum cool setting. The cooling fan should engage within 30-60 seconds of AC activation. Monitor for proper fan operation and listen for abnormal relay clicking sounds.

Reassembly

1. Verify relay box cover is properly secured with both locking tabs engaged
2. Confirm all electrical connections are clean and tight
3. Ensure no tools or parts are left in engine compartment

Verification

• Start engine and run at idle with AC on maximum - cooling fan should activate within 60 seconds
• Allow engine to reach normal operating temperature - fan should cycle on and off as needed
• Turn AC off and on several times to verify relay cycles properly without hesitation
• Listen for proper relay clicking sound during fan engagement
• Check for any warning lights on instrument cluster related to cooling system

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