* Faulty Fuel Level Sender: This is the most common cause. The sender unit, located inside the fuel tank, measures the fuel level and sends a signal to the gauge. If the sender is damaged, corroded, or its float is stuck, it will provide inaccurate readings, often showing empty regardless of the actual fuel level.
* Bad Fuel Gauge Cluster: The gauge itself in the instrument cluster could be malfunctioning. A faulty gauge won't accurately display the signal from the sender, even if the sender is working correctly.
* Wiring Issues: Corrosion, broken wires, or loose connections in the wiring between the fuel level sender and the gauge can interrupt the signal. This is particularly common in older vehicles due to age and exposure to the elements.
* Grounding Problems: A poor ground connection anywhere in the fuel gauge circuit can also cause inaccurate readings.
* Faulty Fuel Pump Relay (Less Likely): While less likely to directly cause an "empty" reading, a faulty fuel pump relay can lead to the engine not getting fuel, and in some cases, this *might* affect the sender unit's ability to send a signal (though it's more likely to just show no change or erratic readings).
Troubleshooting Steps:
1. Check the Fuel Gauge Itself: Does the needle move at all when you turn the ignition on? If it doesn't even move a little bit, the problem likely resides within the gauge cluster itself.
2. Inspect the Wiring: Carefully examine the wiring harness connecting the fuel tank to the instrument cluster. Look for any obvious signs of damage, corrosion, or loose connections.
3. Test the Fuel Level Sender (Most Difficult): This often requires dropping the fuel tank (a messy job), or at least accessing the sender from underneath the vehicle. A multimeter can be used to check the sender's resistance at different fuel levels. You'll need a wiring diagram to know the correct wires to test. Many repair manuals provide this information.
4. Check the Ground Connections: Inspect the ground wires associated with the fuel gauge system. Clean any corrosion and ensure they're making a good connection.
Recommendation:
Unless you're comfortable working on vehicles and have the necessary tools and safety precautions (working with fuel can be dangerous!), it's best to take your 1994 Ranger to a qualified mechanic for diagnosis and repair. They have the expertise and equipment to properly diagnose the issue and fix it safely. Replacing the fuel level sender is a common repair, and while possible for a DIYer, it's often easier for a professional.
