1. Check for Loose Connections:
* Mirror Adjustment Mechanism: The most common cause is a loose connection within the mirror's adjustment mechanism itself. Carefully inspect the mirror arm and its connection points to the vehicle. Look for any loose bolts, screws, or clips. Tighten any that are loose. Sometimes, wiggling the mirror itself while looking for loose parts can help you identify the source of the rattle.
* Wiring Harness: The mirror's electrical wiring harness can become loose or damaged. Inspect the wiring where it connects to the mirror and the vehicle. Look for any frayed wires, broken connectors, or loose plugs. Secure any loose wiring or replace damaged parts.
2. Inspect the Mirror Mount:
* Loose Bolts: Check the bolts that secure the mirror to the door. Tighten them if they're loose. If the bolts are stripped, you'll need to replace them.
* Damaged Mount: Inspect the mirror's mounting bracket for any cracks, bends, or damage. A damaged mount can cause the mirror to vibrate. Replacement might be necessary.
3. Examine the Door Panel:
* Loose Interior Components: Sometimes, a loose component inside the door panel can cause vibrations that transfer to the mirror. Check for anything that might be rattling inside the door. You may need to remove the door panel (carefully!) to inspect this. There are many online resources showing how to do this for your specific year of Expedition.
4. Check for External Factors:
* Aerodynamic Issues: While less likely, excessive wind noise or turbulence at higher speeds could contribute to mirror shake. Consider whether the problem is more pronounced at specific speeds.
* Collision Damage: If you've recently been in a collision, even a minor one, it could have damaged the mirror's mounting or internal components.
5. Consider Professional Help:
If you've checked all of the above and the mirror still shakes, it's best to take your Expedition to a qualified mechanic or Ford dealership. The problem could be more complex, requiring specialized tools or knowledge. They can diagnose the issue more accurately and perform any necessary repairs or replacements.
Before starting any repairs, consult your owner's manual for specific instructions and safety precautions. Removing the door panel can be tricky and requires careful attention to avoid damaging the electrical components or other parts. If you're not comfortable with DIY auto repair, don't hesitate to seek professional help.
