This procedure covers the replacement of the cooling fan relay in the engine compartment relay box on a 2014-2019 Toyota Corolla with the 1.8L I4 engine.

Warnings

Tools required

Parts

• Cooling fan relay × 1 — 90987-02028 or equivalent

Preparation

1. Park vehicle on level ground and turn off engine
2. Allow engine to cool completely if recently operated
3. Open and secure hood in raised position
4. If desired, disconnect negative battery terminal to prevent electrical faults during relay replacement

Procedure

1. 1

   Locate the engine compartment relay box
   The main relay box is located on the driver's side of the engine bay, near the battery. It is a black rectangular box with a removable cover labeled with relay positions.
2. 2

   Remove relay box cover
   Press the tab(s) on the relay box cover and lift upward to remove. The cover may have a relay diagram on the underside showing relay positions and functions.
3. 3

   Identify cooling fan relay location
   Locate the cooling fan relay using the diagram on the relay box cover or owner's manual. The cooling fan relay is typically labeled as 'COOLING FAN' or 'FAN' and is usually positioned in the front row of relays. Note the orientation of the relay before removal.
4. 4

   Remove the old cooling fan relay
   Using needle-nose pliers or a relay puller, grasp the relay firmly and pull straight upward with steady pressure. Do not rock the relay side to side as this may damage the socket terminals. The relay should release from its socket with moderate force.
5. 5

   Inspect relay socket and terminals
   Examine the relay socket for corrosion, bent terminals, or heat damage. Check that all terminal contacts are present and properly aligned. If corrosion is present, clean terminals with electrical contact cleaner and allow to dry completely.
6. 6

   Install new cooling fan relay
   Align the new relay with the socket, ensuring proper orientation by matching the relay terminal configuration with the socket. Push the relay straight down into the socket until it seats fully with an audible click. The relay should be flush with surrounding relays.
7. 7

   Reinstall relay box cover
   Position the relay box cover over the relay box and press down firmly until all tabs engage and the cover is fully seated. Ensure the cover is secure and properly latched.

Reassembly

1. If battery was disconnected, reconnect negative battery terminal and ensure connection is tight
2. Close hood securely

Verification

• Start the engine and allow it to idle
• Turn on air conditioning to maximum setting - the cooling fan should activate within 30-60 seconds
• Allow engine to reach operating temperature and verify cooling fan cycles on and off appropriately
• Listen for normal fan operation without unusual clicking or buzzing from the relay
• Check for any warning lights on instrument cluster related to cooling system
• If available, use a scan tool to check for any cooling system related fault codes

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