Cooling Fan Relay

This procedure covers the replacement of the cooling fan relay in a 2014-2018 Chevrolet Silverado 1500 with the 5.3L V8 EcoTec3 L83 engine, located in the underhood fuse/relay box.

Warnings

Tools required

Parts

• Engine cooling fan relay × 1 — Use OEM specification - typically a 4 or 5-pin micro relay

Preparation

1. Park vehicle on level ground and turn off engine
2. Allow engine to cool if recently operated
3. Open hood and secure with prop rod
4. Locate the underhood fuse/relay center on the driver's side of the engine compartment near the battery
5. Disconnect negative battery cable to prevent electrical short circuits

Procedure

1. 1

   Access the underhood fuse/relay box
   Locate the black plastic fuse/relay box on the driver's side of the engine bay. Release the cover by pressing the tabs on both sides and lift the cover upward. The fuse/relay diagram is printed on the underside of the cover.
2. 2

   Identify the cooling fan relay
   Reference the fuse/relay diagram on the cover to identify the cooling fan relay position. The 2014-2018 Silverado 1500 typically has the engine cooling fan relay marked as 'K47' or similar designation. The relay is usually located in the rear section of the relay box and is a small rectangular component with 4 or 5 pins.
3. 3

   Test the existing relay (optional)
   Before removal, you can test the relay with a multimeter to confirm failure. Check for continuity across the coil terminals and switching function. This step helps verify the relay is actually faulty before replacement.
4. 4

   Remove the faulty relay
   Grasp the relay firmly with needle nose pliers or a relay puller tool. Pull straight upward with steady pressure to extract the relay from its socket. The relay should release from the friction fit socket. If resistance is encountered, gently rock the relay side-to-side while pulling upward. Inspect the relay socket terminals for corrosion or damage.
5. 5

   Inspect relay socket and clean if necessary
   Examine the relay socket for corrosion, bent pins, or debris. If corrosion is present, use electrical contact cleaner and a small brush to clean the terminals. Ensure all socket pins are straight and undamaged. If the socket is severely damaged, the entire fuse/relay box may need replacement.
6. 6

   Install new cooling fan relay
   Align the new relay with the socket, ensuring the pin configuration matches the socket layout. The relay will only fit in one orientation. Press the relay firmly into the socket until it seats completely and is flush with surrounding relays. Ensure all pins are fully engaged in the socket.
7. 7

   Reconnect battery and test operation
   Reconnect the negative battery cable. Start the engine and allow it to reach operating temperature or turn on the air conditioning system to activate the cooling fans. Listen and observe for proper cooling fan operation. The fans should activate when coolant temperature reaches approximately 230°F or when A/C is engaged.
8. 8

   Reinstall fuse box cover
   Once proper fan operation is confirmed, align the fuse/relay box cover and press down firmly until the retaining tabs click into place on both sides. Ensure the cover is fully seated and secure.

Reassembly

1. Ensure the fuse/relay box cover is properly secured with all tabs fully engaged
2. Verify no tools or parts are left in the engine compartment
3. Close the hood and verify it latches properly

Verification

• Start the engine and turn on the air conditioning system to maximum - both cooling fans should activate within 10-15 seconds
• Allow the engine to reach normal operating temperature and verify the cooling fans cycle on and off as needed
• Check for proper engine temperature reading on the instrument cluster - should stabilize around 210°F
• Listen for abnormal noises from the cooling fan area during operation
• Verify no warning lights are illuminated on the instrument panel related to engine temperature

Related trouble codes on this vehicle

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