1. Consult your owner's manual: This is the best place to start. It should have a diagram showing the fuse box layout and identifying the blower motor relay.
2. Locate the under-dash fuse box: This is usually located on the driver's side, near the steering column.
3. Look closely at the fuse box: Some fuse boxes have the relays integrated into them. Others may have a separate relay panel nearby. Check for markings that identify the blower motor relay (it may be labeled, or you might need to cross-reference it with your owner's manual).
4. If it's not in the fuse box: It's possible the relay is located elsewhere, perhaps attached to the blower motor itself under the dash. This is less common but possible. Accessing this area may require removing some trim panels.
Important Note: Working with electrical components can be dangerous. If you are uncomfortable working on your vehicle's electrical system, it's best to take it to a qualified mechanic.