1. Check Fuse: First, check the fuse responsible for the blower motor. A blown fuse could be the reason why the fan stopped working.
2. Locate Blower Motor Relay: Usually located in the underhood fuse box or junction box. Consult your vehicle's specific service manual for the exact location.
3. Test Blower Motor Relay: Use a multimeter to test continuity across the relay contacts. Replace the relay if it's faulty.
4. Check for Power: Use a multimeter to check if there's power going to the blower motor connector while the fan switch is turned on.
5. Disconnect Blower Motor: Disconnect the electrical connector to the blower motor.
6. Apply Direct Power: Use jumper wires to connect a power source directly to the blower motor, bypassing the relay and switch. If the motor runs when connected directly, it means the relay or switch could be the issue. If the motor still doesn't run, there's a possibility the motor itself is faulty.
If the relay turns out to be defective, here's how you can find and fix the issue:
- Locate Blower Motor Assembly: It's typically installed behind the dash on the passenger side, or sometimes under the vehicle next to the firewall. The service manual for your Jeep should provide specific disassembly instructions.
- Inspect Wiring: Visually examine the wiring connected to the blower motor relay for any visible damage, looseness, or corrosion. Ensure the connectors are properly seated and the wires are intact.
- Replace Blower Motor: If the motor proves to be faulty, you'll need to replace it. The exact steps may vary slightly from model to model, but it generally involves removing the old motor, disconnecting the wiring, and installing the new motor correctly. Refer to your vehicle's service manual for detailed instructions specific to your Jeep.
For both solutions (fixing the relay or motor), proper testing with a multimeter, careful examination of components, and following your vehicle's repair manual are essential for effectively diagnosing and resolving the issue of your Grand Cherokee's fan not blowing. If at any point during the process you feel unsure or encounter difficulties, it's best to consult a certified mechanic or auto repair professional to ensure that your vehicle is adequately and safely repaired.