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Ford F150 License Plate Lights Not Working

Ford F150 License Plate Lights Not Working

License plate lights in Ford F150 are installed to show the rear number plate, especially at night and in unfavorable weather. It is illegal if you do not have these lights on the rear of your vehicle.

Ford F150 License Plate Lights do not work due to a short circuit, bad fuse, presence of rust, defective relay, broken bulbs, and faulty BSI box.

Careful inspection of all these issues at the right time can prevent you from difficulties in the future.

Try to take your vehicle to your mechanic at the end of every week so that he can inspect it and save you from troubles during the ride.

Corroded license plate

Corrosion is the cause of many issues behind the non-functioning of various car features, especially those which are electrically operated. The working is affected because the corrosion deteriorates the inner parts of components.

Corrosion is the process of wasting away metal due to excessive exposure to water. It happens because of factors like the pH of water, concentration of oxygen, and temperature, which is not suitable.

Check the license plate of your truck for corrosion first if you experience a failure in operating the lights. Clean the area where lights are located and lie down under your Ford to pull the bulb out.

Always check the bulb first when you face the issue of lights not working. You can check the bulb yourself by lying down under your Ford F150.

Behind the license plate, you can find the socket of the bulb. Twist before pulling the socket out and remove the bulb from it.

Inspect the socket and look for signs of corrosion. The winner of the socket becomes badly corroded, making it impossible for power to reach the bulb. You can replace it with a new socket which is around $12.

Defective relay switch

Relay switch controls the gadgets of the car working with the help of electricity, like the license plate light in the Ford F150. So there is a good possibility that the relay of your vehicle is bad if the lights are not working.

Relay switches are present in the fuse panel, and it contains four pins numbered 85, 86 for the control circuit and 87, 30 for the load circuit.

There are two relays for one component with the same number written on it, and often swapping them can resolve the issue with lights.

Relays work when you turn on the switch for lights to send the power into the circuit and to its coil. The power goes to pins 85 and 86 to the ground on 87 and 30 to complete the circuit. 

The lights turn on when the battery sends the current to pin 87, and then it leaves the relay back to the battery through the pin to the circuit of the lights. 

Run a test which is called a click test in which you hear a clicking sound if the relay is not faulty.

Take wires from the battery and touch them to the switch’s pin, and if you cannot hear the sound, then the relay is bad.

Bad fuse

A fuse is a metal filament closed in a plastic covering and with switches on the outside. There are a few others in a fuse box in different small compartments. 

It gets worse because it is bearing a heavy load which is more than its capacity. Moreover, adding new electronics in the car which are not installed in the factory-made vehicle causes overload and failure of a fuse.

There is an owner manual in your Ford F150 through which you can understand the functions of every fuse.

It is a diagram like a flow chart in which fuses are labeled with a number to help you find them if you face any problem.

Open the fuse box and inspect them with your eyes first. You can identify the bad fuse if its inner metal filament is broken or burned and replace it with the same amperage fuse. 

The other way of checking the fuse is by using a test light if you do not see any breakage of the wire.

Put the clip on the ground and touch the pin of the test light on the power to check if the light turns on. Now, put the probe on the fuse to see if it turns on and if there is no light on the license plate, then the fuse is bad.

Short circuit

A short circuit occurs when the wiring in your Ford F150 is faulty, and it causes the electricity to pass to the ground through a path not intended for it. There are different reasons for short circuits, such as loose and corroded wires.

A circuit can happen in two ways; if the current is flowing through the body of the car to the ground instead of passing from the right path made for it.

The second way a short occurs is when the current goes back to power instead of flowing to the circuit. 

You can find the short circuit with the help of a battery charger by attaching the positive and negative leads to the spots intended for them.

You have a short circuit issue when you turn the charger on and experience any spark or heat coming from it.

You can fix the short circuit issue in your Ford with the help of some tools. Locate the site of the short circuit and take a new wire to replace it with the damaged wire. Measure the length of the new wire with the old one and cut it.

Take a utility knife and remove the insulations from the wire end to make enough exposure so that new wires can be attached to them. Attach them and solder the contact points with a soldering gun.

Now put the wires into their intended circuit and turn on the system. The fixing is successful if you do not see sparks or heat coming from it and the license plate light is working correctly.

Faulty BSI Box

A BSI box called a built-in system interface is an electronic control unit. It works like a brain for your Ford F150 to control all the electric-based features of the car.

For example, it prevents the interior of the automobile from crossing the wires and helps with the connection of computers.

Your Ford can stop working if this box is damaged, and you can face speeding issues of the engine and failure to turn the license plate lights on.

The diagnosis of the problematic BSI is not easy because the faulty BSI box gives signals like fuse and battery.

An expert technician can detect this issue, so you better contact one if you have performed all the above diagnoses.

Only experts have the skill and diagnostic tools for detecting this problem. The problem with the box is checked with the help of a software module in Ford.

The BSI box is a complex system, and you cannot repair it in case of failure.

You better contact your Ford technician because he can guide you and resolve the issue with his expertise. This box is expensive, and it costs about $150 for a used one.

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