Here's a general outline. Always consult a repair manual specific to your vehicle's year and model for the most accurate and detailed instructions. A Haynes or Chilton manual is a good investment for DIY car repairs.
1. Disconnect the Battery: This is crucial to prevent electrical shocks and short circuits. Disconnect the negative (-) terminal first.
2. Remove the Wiper Arms: You'll need a wiper arm puller tool (available at most auto parts stores) to safely remove the wiper arms. These are usually held on by a nut under a plastic cover. Note the position of the arms before removing them, so you can replace them correctly.
3. Remove the Wiper Cowl: This is the plastic cover that sits over the wiper mechanism. It's usually held in place by clips or screws. Carefully pry it loose, paying attention to how it's attached to reassemble it later.
4. Access the Wiper Motor: Once the cowl is removed, you should have a clear view of the wiper motor. You may need to disconnect some electrical connectors and potentially remove some linkage components connected to the motor.
5. Remove the Wiper Motor: The motor itself will likely be held in place by nuts and bolts. Unscrew these, and carefully remove the motor.
Important Considerations:
* Photographs: Take pictures of every step of the disassembly process. This will be invaluable when reassembling.
* Wiring Diagram: A wiring diagram is highly recommended to ensure you reconnect the electrical connectors correctly.
* Patience: This is not a quick job. Take your time and be methodical.
* Professional Help: If you're not comfortable with this type of repair, it's best to take your Grand Marquis to a qualified mechanic. Improper repair can lead to further damage or injury.
This information is for guidance only. Always refer to a repair manual specific to your vehicle before attempting any repairs. Incorrect procedures can damage your vehicle or cause injury.
