The fuel level sender is located in the fuel tank on the driver's side. It is attached to the fuel pump assembly.
Here's a step-by-step guide to access and replace the fuel sensor (fuel level sender) in a 1996 Mercury Mystique:
1. Relieve Fuel Pressure:
Before you begin, you must relieve the fuel pressure in the fuel system. For the Mystique, this can be done by removing the fuel pump fuse (labelled as "FP") located in the underhood fuse box. Start the vehicle and let it run until it stalls. Then, crank the engine a few more times to ensure all fuel pressure is relieved.
2. Disconnect Battery (Optional):
For added safety, you may disconnect the negative terminal of your vehicle's battery before working near the fuel tank and fuel system.
3. Locate Fuel Tank Access Port:
In the trunk of the Mystique, underneath the carpet near the rear passenger's seat, there is a plastic cover. Remove the plastic cover to access the fuel tank access port.
4. Remove Fuel Tank Access Cover:
There might be a bolt securing the fuel tank access cover. Use a wrench or socket to remove this bolt and lift the access cover to expose the fuel tank and components beneath.
5. Locate Fuel Pump Assembly:
Inside the fuel tank, you'll see the fuel pump assembly and the fuel level sender attached to it. The sender is usually held in place by a lock ring or retaining ring.
6. Disconnect Electrical Connectors:
Before removing the fuel level sender, disconnect the electrical connectors attached to the fuel pump assembly and the sender itself. Note the positions and orientations of the connectors for reinstallation.
7. Remove Lock Ring or Retaining Ring:
Locate the lock ring or retaining ring that secures the fuel level sender to the fuel pump assembly. Use the appropriate pliers to carefully pry open or remove the lock ring or retaining ring.
8. Remove Fuel Level Sender:
Once the lock ring or retaining ring is removed, you should be able to lift and remove the fuel level sender from the fuel pump assembly. Inspect the sender for any signs of damage or corrosion.
9. Install New Fuel Level Sender:
If necessary, replace the fuel level sender with a new unit. Make sure the replacement sender is compatible with your vehicle's specifications. Insert the new sender into its designated location and secure it using a new lock ring or retaining ring.
10. Reconnect Electrical Connectors:
Reattach the electrical connectors that you disconnected earlier. Ensure they are firmly connected.
11. Reinstall Fuel Tank Access Cover:
Replace the fuel tank access cover, making sure it's securely fastened. If there was a bolt holding the cover in place, reinstall it as well.
12. Replace Trunk Carpet:
Reinstall the trunk carpet after replacing the fuel tank access cover.
13. Reconnect Battery (Optional):
If you disconnected the battery earlier, reconnect it now.
14. Reset Fuel Trim:
In some cases, resetting the fuel trims on the vehicle's computer might be necessary after replacing the fuel level sender. Consult your vehicle's service manual for specific instructions on resetting fuel trims.
Note: Before performing any work on your vehicle's fuel system, it's important to take proper safety precautions. Work in a well-ventilated area, avoid sparks or flames, and be careful when handling fuel. If you're not confident in your ability to perform this task or have concerns about fuel system safety, it's best to seek assistance from a qualified mechanic.
