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Ford F150 Auto Dimming Rear View Mirror Not Working

Ford F150 Auto Dimming Rear View Mirror Not Working

There are different reasons due to which Ford F150 Auto Dimming Rear View Mirror stop its functioning. The damage in the wiring, faulty sensors, gel leakage all contributes to its malfunctioning. The discoloration and breakage during an accident also decrease its functionality. 

This truck has many beneficial features, one of them is the auto-dimming rearview mirror. This mirror helps the driver in viewing things clearly in day and night conditions.

Ford F150 Auto-Dimming Rear-View Mirror Not Working

The Ford F150 contains an auto-dimming rearview mirror. This mirror works by changing itself from normal and non-glare conditions into an automatically dimming state.

During the night, the bright lights come from the vehicle behind your truck strike with them.

The mirror measures the intensity of the bright light and adjusted in such a way as to lower down the light glaring.

It helps the driver to see the traffic behind his truck clearly without putting stress on his eyes. 

It can also protect the driver behind your vehicle because when light strikes, it reflects.

It also dims the light reflection and protects the eyes of the driver behind you. In this way, the mirror saves everyone from mishaps. 

There are several reasons due to which these mirrors stop working and do not dim down the glare. Some of the reason for its malfunctions is as below:

Faults in the sensor of the auto-dimming mirror

There are two sensors attach to the auto-dimming mirrors.

The sensor provides safety in heavy traffic roads and protects the driver from reduced visibility. There are two sensors, i-e, the ambient sensor and the glaring one.

The ambient sensor detects all the lights coming into the vehicle.

This sensor senses the low-intensity beam of light. It sends feedback to the control center to start the diming action.

The glare sensor detects the high-intensity light falling on the glass and sends a message to the control unit; place it in this mirror.

These control units inspect the responses of sensors and send the output in the form of diming.

Sometimes due to fault in any of these sensors, the auto-dimming action of this mirror is disrupted.

There is also an internal trigger system present that sends messages to the control unit.

The malfunctioning in any of these components makes the mirror malfunction. It does not perform the task of dimming. 

You can check the working of the sensor by seeing the surface of them. If any substance present on the sensor surface like dust, debris, or some tape.

The sensor will not perform its activity accurately. Use a soft cloth to clean up the covering of the sensor. Check for scratches which also disrupt the functioning of the sensors. 

You can check the internal trigger and the sensor by using a voltmetre. If the sensor is not working after performing all these adjustments, you need to change it as quickly as possible.

Wiring damage

The auto-dimming of the rearview mirror works on the power supply. Turn the ignition ON in the truck, the power supplies to them. 

There is a hot wire that connects with the instrumental panel and the auto-dimming mirror. This wiring runs from the headliner towards the mounting mirror. 

The wiring supplies power to the mirror when the ignition is ON and when you start to reverse your vehicle. The possible reason which makes the mirror stopped working is the damage in its wiring. 

The auto-dimming also disrupts if the wiring connection is loose. You need to check the wiring with the help of a voltmeter. If there is no voltage in the voltmeter, change the whole setup.

You can also perform electrical and lighting inspections in your truck. 

It is vital to treat your rearview mirror as soon as possible because of safety preferences. 

The glaring increases the chances of accidents because it can continuously affect the eyes of the driver.

It can also decrease your response time towards any calamity. The reason it is essential to use these auto-dimming mirrors. 

Check the mirror wiring in the truck; if it operates accurately, the culprit is in the mirror.


The position of this mirror also affects its functionality. There is the continuous presence of sunlight and dust when the window is open.

As a result of this problem, sometimes the mirror becomes discolored. The auto-dimming mirror is in continuous use for setting it in an accurate position so you can easily see through it. 

The debris that comes from your hand also affects its functionality and makes them discolored. 

You can fix this issue; using a soft cloth that does not give any scratches to its surface. Clean the surface of the mirror and its sensors.

Discoloration usually occurs from the bottom of the mirror; try to clean it precisely, then check its auto-dimming function.

If the mirror does not show any sign of automatically dimming, then there are high chances that your mirror is damaged.

Try to replace them with the new one of the same functionality. 

Damages in the glass of the mirror

The auto-dimming mirror work on the principle of electrochromism. There are two layers present inside it. The front layer composes of the glass panel behind this mirror attached. 

Light strokes on the glass, the glare detects by the sensors and sends a message to the control unit. There are different conductive layers present between the glass and the mirror. 

They are present in such a sequence that ion storage comes first, then the electrolytes, and after that layer of the electrochromic present. 

The control unit sends the instruction of auto-dimming. The system uses electrical voltage between these layers, and the ions start to move towards the electrochromic layer.

In this way, the glaring of the light starts to fade to an appropriate level. Sometimes due to accidents, the glass becomes damaged, and the gel inside it starts to lose.

It is necessary to check the gel quantity and fix it.

If the gel leaks out from it, change the mirror immediately because its functionality disrupts.

The tinted window is the culprit

The tinted window is a new standard inside society. 

People use to change their original windows with tinted ones. 

It will directly impact the functionality of the mirror. Tinted windows can act as a barrier between the sensor and the light.

Check the functioning of these mirrors by striking direct light on them from the inside of the truck. You will see that the mirror starts to dim.

In this situation, try to change your tinted windows to normal ones. So you can achieve the anti-glaring effect of your rearview mirrors.

How do auto-dimming rear view mirrors work?

The auto-dimming mirror performs its task with the help of a sensor.

The sensors detect the bright light intensity from the back of the truck. They have two parts interior mirror and exterior glass. 

When the sharp light falls on the exterior glass, the sensors detect them, and they activate the interior mirror. As the result of interior mirror activation, the exterior one starts to shade down. 

They dim to an accurate level so that the driver can easily see behind him. Try not to block the senors’ route, located on the front and backside of the mirror.

It will disturb the functionality of the sensor. Sometimes the incorrect angle of the mirror also affects its working.

The head restraint and the passenger seating on the center of the truck block the route of light and disturbs the working of sensors.

The mirrors can automatically return to their original state during the daytime. It can also return to its normal state when the driver starts to reverse the pickup. So the driver can see behind him. 

Why should you repair it?

There are different laws regarding the use of this mirror because they decrease the number of accidents. They are necessary for the safety of drivers.

The malfunctioning of this mirror affects the driving during nighttime. The driver can lose its focus on the road and the steering wheel.

The driver behind you also gets distracted because of the direct reflection of light through the mirrors.

Sometimes due to accidents, the mirror breaks or falls off from its mounting place.

It is necessary to buy a new one and mount it in its original mounting place as soon as possible. In this way, you will save yourself from heavy fines and prevent accidents.

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