Signs Your Neutral Safety Switch Needs Replacing:
* Intermittent Starting: The car sometimes starts, sometimes doesn't, even when the gear selector is in Park or Neutral. This is the most common symptom.
* No Start: The car completely refuses to start, even with the key in the "on" position and the gear selector in Park or Neutral.
* Car Starts in Gear (Dangerous!): This is a serious safety issue. If the car starts while in Drive, Reverse, or any gear other than Park or Neutral, the NSS is definitely faulty and needs immediate replacement.
* Electrical Issues (Less Common): In rare cases, a failing NSS can cause other electrical problems, such as malfunctioning accessories or dashboard lights.
Replacing the Neutral Safety Switch:
This is a moderately challenging job, requiring some mechanical aptitude. Before you begin, disconnect the negative battery cable to prevent accidental shorts.
1. Locate the NSS: On a 1989 Lincoln Mark VII, the NSS is typically located on the transmission itself, near where the shift linkage connects. You'll likely need to consult a repair manual specific to your vehicle year and model to pinpoint its exact location. A repair manual will also show you diagrams and provide precise instructions.
2. Gather Tools: You'll need:
* Socket wrench set (metric)
* Ratchet
* Extension(s)
* Possibly a pry bar or small screwdriver (to help disconnect the linkage)
* New neutral safety switch (ensure you get the correct part number for your vehicle)
* Wire connectors (if necessary)
* Safety glasses and gloves
3. Disconnect the Electrical Connector: Carefully unplug the electrical connector from the NSS. Take a picture or make a note of which wire goes where before disconnecting to ensure correct reconnection.
4. Disconnect the Linkage (if necessary): The linkage connecting the shifter to the transmission might need to be loosened or disconnected to access the NSS. Again, your repair manual will be essential here.
5. Remove the Old NSS: Using the appropriate socket and ratchet, carefully remove the bolts holding the NSS in place. It may be slightly stubborn; use a gentle but firm approach to avoid damaging anything.
6. Install the New NSS: Carefully install the new NSS, ensuring it's seated correctly. Tighten the bolts to the manufacturer's specifications (found in your repair manual).
7. Reconnect Everything: Re-connect the linkage, the electrical connector (making sure wires are correctly positioned), and the negative battery cable.
8. Test: Attempt to start the car. It should only start when the gear selector is in Park or Neutral. Test starting in each gear position to confirm it's functioning correctly.
Important Considerations:
* Repair Manual: Strongly recommended. A Haynes or Chilton manual will provide detailed diagrams and instructions.
* Safety: Disconnect the negative battery cable before starting. Be cautious when working around the transmission and electrical components.
* Part Number: Get the correct replacement NSS for your specific vehicle. The wrong part will not work.
* Professional Help: If you're not comfortable performing this repair yourself, take your car to a qualified mechanic. A wrongly installed NSS can create serious safety issues.
By following these steps and consulting a repair manual, you should be able to diagnose and replace the neutral safety switch on your 1989 Lincoln Mark VII. Remember, safety is paramount – if you're uncertain about any step, seek professional assistance.
