1. Identifying the Problem:
* Broken Mount: Is the mount itself cracked or broken? This usually means replacing the entire mount, which might require some bodywork if the damage is significant.
* Faulty Aerial (Antenna): Is the antenna itself damaged or malfunctioning? This is a simpler fix, usually just involving unscrewing the old antenna and screwing on a new one.
2. Accessing the Mount:
* Removing Interior Trim: You'll likely need to remove some interior trim pieces around the roof area where the antenna is located. This usually involves carefully prying off plastic panels with trim removal tools to avoid scratching the paint. Consult a repair manual (Haynes or Chilton) specific to your 2003 Ford Focus for detailed instructions on trim removal for your particular model. Generic online videos might not be exactly accurate for your car.
* Locating the Mount: Once the trim is off, you'll see the antenna mount itself. It's usually attached to the roof with nuts and bolts, or possibly just screws. Again, a repair manual is your best friend here.
3. Replacing the Antenna (Simpler Case):
If the mount is intact but the aerial is bad:
* Disconnect the Coax Cable: Carefully disconnect the coaxial cable (the cable that connects the antenna to the radio) from the base of the antenna. Take a picture or make a note of how it's connected to avoid confusion during reassembly.
* Unscrew the Antenna: Most antennas are simply screwed onto the mount. Unscrew the old antenna.
* Screw on the New Antenna: Screw the new antenna onto the mount, ensuring it's tightened securely.
* Reconnect the Coax Cable: Carefully reconnect the coaxial cable.
* Reassemble Trim: Carefully reinstall the interior trim pieces.
4. Replacing the Mount (More Complex Case):
If the mount itself is damaged:
* Disconnect the Coax Cable: As above.
* Remove the Mount: This is where it gets tricky. You'll likely need to remove the nuts and bolts securing the mount to the roof. This may require specialized tools. Use the correct size sockets to avoid damaging the nuts or bolts.
* Install the New Mount: Carefully install the new mount, making sure it's securely fastened. Use new nuts and bolts if needed.
* Reconnect the Coax Cable and Antenna: Connect the coax cable to the new mount and then attach the antenna.
* Reassemble Trim: Reinstall the interior trim.
Important Considerations:
* Repair Manual: A repair manual specific to your 2003 Ford Focus is essential. It will show you exactly where the screws/bolts are, what trim pieces need to be removed, and the proper procedure.
* Tools: You'll need trim removal tools (plastic pry tools), possibly sockets and wrenches, and potentially a sealant to ensure a watertight seal around the new mount if necessary.
* Patience: This is not a quick job. Take your time and be careful to avoid scratching or breaking any parts.
If you're uncomfortable doing this yourself, it's best to take your car to a qualified mechanic or auto body shop. Improper installation could lead to water leaks or damage to your car's electrical system.
