Cooling Fan Relay

This procedure covers the replacement of the cooling fan relay in the 2023 Chevrolet Bolt EUV, which controls the operation of the electric cooling fans for the battery thermal management system.

Warnings

Tools required

Parts

• Cooling fan relay × 1 — Use OEM specification
• Dielectric grease packet × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Turn off vehicle and remove key fob from interior
3. Open hood and secure with prop rod
4. Locate 12V battery in engine compartment (passenger side)
5. Disconnect negative (-) terminal on 12V battery and isolate cable

Procedure

1. 1

   Access underhood fuse and relay center
   Locate the underhood fuse and relay center on the driver side of the engine compartment, near the front bulkhead. Release the two cover tabs by pressing down and pulling outward, then lift the cover off to expose the relays and fuses.
2. 2

   Identify the cooling fan relay
   Consult the diagram on the underside of the fuse box cover or the owner's manual to identify the cooling fan relay location. In the 2023 Bolt EUV, the cooling fan relay is typically located in the upper row of relays and is labeled on the diagram. Verify identification before removal.
3. 3

   Test the existing relay (optional)
   If diagnosing a cooling fan issue, use a multimeter to test the relay terminals for continuity before removal. Check for power at terminal 86 and ground at terminal 85 with ignition on. This step helps confirm the relay is the failed component.
4. 4

   Remove the cooling fan relay
   Grasp the relay body firmly and pull straight up with steady pressure to remove it from the socket. If resistance is encountered, use a relay puller tool to avoid damaging the socket terminals. Do not rock the relay side-to-side as this can bend socket pins.
5. 5

   Inspect relay socket and terminals
   Examine the relay socket for signs of corrosion, burnt terminals, or damage. Check that all four socket pins are straight and properly aligned. If corrosion is present, clean terminals with electrical contact cleaner and a small wire brush. If terminals are burnt or damaged, the entire fuse box may require replacement.
6. 6

   Install new cooling fan relay
   Apply a small amount of dielectric grease to the relay terminals to prevent corrosion. Align the new relay with the socket, ensuring proper orientation (relay will only fit one way). Press firmly straight down until the relay is fully seated and clicks into place. Verify all four pins are properly engaged.
7. 7

   Reinstall fuse box cover
   Position the fuse box cover over the relay center, aligning the hinge tabs at the rear. Press down firmly on both sides of the cover until the locking tabs click into place. Verify the cover is secure and fully seated.
8. 8

   Reconnect 12V battery
   Reconnect the negative (-) terminal to the 12V battery. Tighten the terminal clamp securely but do not overtighten. Ensure the cable cannot come loose during vehicle operation.

Reassembly

1. Ensure all fuse box cover tabs are fully engaged and secure
2. Verify no tools or parts were left in the engine compartment
3. Close hood and verify proper latch engagement

Verification

• Turn vehicle to ON position (do not start) and monitor for any electrical fault codes on the instrument cluster
• Start the vehicle and allow it to idle for 2-3 minutes
• Turn on the climate control system to maximum cooling to trigger fan operation
• Listen for cooling fan activation - fans should engage smoothly without unusual noises
• Verify both cooling fans operate at variable speeds as commanded by the thermal management system
• Use a scan tool to command cooling fans ON/OFF to verify relay functionality (optional)
• Check that no cooling system warning lights appear on the dashboard

Related trouble codes on this vehicle

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