Cooling Fan Relay

This procedure covers the removal and replacement of the cooling fan relay in the underhood fuse box of a 2015-2020 Ford F-150 with the 5.0L Coyote V8 engine.

Warnings

Tools required

Parts

• Cooling fan relay × 1 — Use OEM Motorcraft relay or equivalent 40A automotive relay

Preparation

1. Park vehicle on level surface and engage parking brake
2. Turn off engine and allow to cool if recently running
3. Open hood and secure with prop rod

Procedure

1. 1

   Locate the underhood fuse/relay box
   The underhood power distribution box is mounted on the driver side fender well near the battery. It is a black rectangular box with a cover.
2. 2

   Remove the fuse box cover
   Press the release tabs on both sides of the fuse box cover and lift upward to remove. The cover may have a diagram showing relay and fuse positions on the underside.
3. 3

   Identify the cooling fan relay
   Locate the cooling fan relay using the diagram on the fuse box cover or owner's manual. It is typically labeled as 'COOLING FAN' or 'FAN RELAY' and is usually a mini relay (smaller than standard relays). Common location is position R2.16 or similar, but verify with your specific vehicle's diagram.
4. 4

   Test the old relay (optional)
   If diagnosing a cooling fan issue, test the relay before removal. With engine at operating temperature and A/C on, listen for relay clicking. You can also use a multimeter to check for continuity and proper switching operation.
5. 5

   Remove the cooling fan relay
   Grasp the relay firmly with needle nose pliers or a fuse puller and pull straight up with steady pressure. The relay should release from its socket. Avoid rocking side to side as this can damage the socket terminals.
   ⚠Do not force the relay. If it does not pull out easily, ensure you have the correct component identified and check for any retaining clips.
6. 6

   Inspect the relay socket
   Examine the socket terminals for corrosion, burning, or damage. Clean any corrosion with electrical contact cleaner if present. If terminals are damaged or melted, the entire fuse box may require replacement.
7. 7

   Install the new cooling fan relay
   Align the new relay pins with the socket terminals, ensuring proper orientation. The relay should only fit one way. Press firmly straight down until the relay is fully seated and flush with surrounding relays.
8. 8

   Reinstall the fuse box cover
   Position the cover over the fuse box and press down firmly until the tabs click into place on both sides. Ensure the cover is fully secured.

Reassembly

1. No additional reassembly required beyond installing the new relay and replacing the fuse box cover

Verification

• Start the engine and allow it to reach operating temperature (approximately 195-210°F)
• Turn on the air conditioning to maximum cooling
• Verify the cooling fan engages and operates at high speed
• Listen for the relay clicking when the fan cycles on and off
• Check that engine temperature remains in normal range and does not overheat
• If fan does not operate, recheck relay installation and consider testing fan motor and wiring

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