Ford Mustang Key Not Working – What To Do?

The Ford Mustang has been one of the most popular muscle cars since its first debut in the '60s. Its smooth ride, raw power, and sleek body style have been the reason why consumers have remained loyal through all of these years.

While this remains true, what happens when the key to your Ford Mustang isn't working? Don't panic because we have researched and found the different reasons why your Ford Mustang Key isn't working. 

Here is the list of reasons as to why your Ford Mustang key isn't working:

  • Dead car battery
  • Blown fuse
  • Dead key battery
  • Key needs to be reprogrammed

Whether it's your Ford Mustang or any other vehicle, it isn't fun if the key isn't working. Cars are complicated, and troubleshooting an issue such as a dysfunctional key can be a pain in the rear. Nonetheless, before you call the mechanic, read on as we talk more about troubleshooting your Mustang key not working and how to address the issue.

Ford Mustang Key Not Working - Diagnosing The Problem

The Ford Mustang was at the beginning of the sports car era and hasn't gone anywhere since. It may be considered an old-school car, but like its competitors, the Dodge Challenger and Chevy Camaro, it has been able to keep up with the times when it comes to technology. 

The new technology has come from blind-spot monitoring, land departure assistance, adaptive cruise control, and even self-driving technology. Another thing that has been big in the car tech world is keyless entry and push to start. 

While this type of tech is handy, it can malfunction like any other type of computer software. Sometimes, tech issues in cars aren't always the tech itself but a combination of issues within the vehicle. 

Below, we break down the different reasons why your Ford Mustang key isn't working and how to troubleshoot the issue. 

Red Ford Mustang GT coupe parked in the town center

Dead Car Battery

One common reason that your key isn't working on your Ford Mustang is that the car battery is dead.

Attempting to push-start or insert your car key without any reaction from the ignition could indicate a dead battery.

Should you possess a battery tester, utilize it to check if a significant amount of voltage is held. Lacking a battery tester? Connect the battery to jumper cables and attempt to jump-start the vehicle.

In case that method fails, inspect the vehicle's interior lights. A functioning battery is likely if either the interior lights or the headlights turn on.

Blown Fuse

While the reason your Ford Mustang isn't starting may be due to a blown fuse, it is unlikely. However, consumers should still check under the hood to see if there is any sign of a blown fuse. A blown fuse to the battery or vehicle's computer could be the reason why the vehicle isn't recognizing the car's key. 

To check for a blown fuse, pull it out of Mustang's fuse box using a fuse puller or needle nose plier and hold it against the light. If the metal strip is broken in the middle, the fuse has blown. You must replace it with one of the same amperages and, therefore, the same color.

If you feel comfortable checking for blown fuses, then do as above. Still, if you are not comfortable replacing the fuse, then it is recommended to contact your local mechanic for assistance. 

Dead Key Battery

Car keys are getting advanced like the rest of the vehicle's tech. Now, they require certain programming in order to do commands such as lock, unlock, remote start, and open the trunk.

With that being said, the key's battery may have died, so the key isn't working. For consumers who have a Ford Mustang with a push-to-start, it is recommended to hold the key fob up to the push-start as close as possible and try starting the vehicle again.

If that doesn't work, and you know that the car battery itself isn't dead, then replacing the key battery should be your next step. Replace the key battery as instructed in the owner's manual and then test it again to see if that solves your issue. 

If replacing the key battery didn't work, then read on as we continue to troubleshoot as to why your Ford Mustang key isn't working. 

Key Needs To Be Reprogrammed

In our digital age, myriad frequencies permeate the air. Devices like cell phones, radios, and cars utilize distinct frequencies. Sometimes, these can cross paths, leading to disconnections.

If, after checking the first three causes, your Mustang key still isn't functioning, a disconnected battery could be the culprit. Key fobs necessitate explicit programming to sync with the vehicle. Occasionally, they disconnect.

Why Reprogramming May Be Necessary

Much like a transponder car key, when the key fob malfunctions, signaling issues are typically at play. Usually, low or dead batteries in the key fob are to blame. Yet, if battery replacement doesn’t resolve the problem, further electronic troubleshooting is needed.

Do you have a spare key fob that works? You're in luck! Take your vehicle and the malfunctioning key fob to your local dealership for reprogramming. Many dealers, especially if you bought the vehicle from them, will reprogram the key at no charge.

DIY Reprogramming Guide

What if you don't have a spare? Here's a simplified guide on how to reprogram or add a new key to your Ford Mustang's Passive Anti-Theft System (PATS) without a programmer:

  1. On-Board Programming:

    • To initiate a new master key:

      1. Insert the new key into the ignition and turn it to the ON position. Wait for the security light on the dash to flash for fifteen minutes.
      2. Turn the ignition OFF, then back to ON, waiting for another fifteen minutes of flashing.
      3. Repeat the OFF and ON cycle one more time, waiting for fifteen minutes.
      4. After the third cycle, the new key is programmed and will operate the car.

    • To add a new key:

      1. Insert an existing key into the ignition.
      2. Turn the ignition to ON, then back to OFF.
      3. Remove the existing key, insert the new key, and turn it ON within 15 seconds. The security light will light up for two seconds to indicate successful programming.

If the problem persists, contacting a local Ford dealer for professional assistance is advisable.

How Do You Start A Mustang With A Dead Key?

If you know for a fact that the key fob battery is dead and you can't get into the vehicle, then rest assured that you aren't entirely out of luck. 

In the event of a dead battery and you're unable to unlock the doors, you open the key fob and then insert the key blade underneath the driver's door handle where there is a lock.

It will unlock the door, and then you can pop your hood and get jumped. Just use the start button as you would a key to turn.

Reference to the video below on how to start your Ford Mustang with a dead key fob:

What Do You Do When Your Car Doesn't Recognize Your Key?

Follow these steps to troubleshoot the issue: 

  • Check the owner's manual to see if the automaker installed a backup solution for starting the car if the key dies.
  • Look for a hidden slot near the steering column that might not be obvious at first.
  • Press the start button with the actual key itself. Some cars can still detect dead key fobs this way in emergencies.
  • If it's a cold day, go indoors and warm up the key fob with your breath. Sometimes, the temperature can mess with the electronics.
  • If you have a second key fob, try using it. This should at least show you if the problem is the key or the car.
  • Replace the battery in the key fob with a new one (use a coin or screwdriver to pop it open).

How Much Does It Cost To Replace A Mustang Key?

The cost of replacing a key for a Ford Mustang will depend on which model it is. Typically, the cost of replacing a Ford Mustang key can range from $140 to $340. This may seem like a broad price estimate, so it is recommended to contact your local dealer to get an accurate price quote for a key replacement. 

How Do You Open A Mustang Without A Key Fob?

Even if your key fob isn't working, there are ways you can still open your Ford Mustang. The key fob on your car will have a physical one within it. Take the key out and look for a key entry underneath the driver's door handle. Insert the key into the entry, and you will be able to open the car doors manually. 

Refrain from putting other objects into the key entry, such as a paper clip or flat-head screwdriver. Using foreign tools like this can cause more damage to the vehicle and possibly set off the car's security alarm. 

In Closing

As the years pass, technology gets more advanced. While technology in vehicles can be convenient, it can also cause issues in the long run. If your Ford Mustang still isn't starting after following this article, then contact your local Ford dealer for assistance. 

If you enjoyed this article on the Ford Mustang, then you might also like the following:

21 Types Of Ford Cars [And That's Without Trucks]

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