Common Symptoms of a Faulty Ford Mustang Courtesy Light Kit
The Ford Mustang courtesy light kit is found on the ceiling of each passenger compartment and is used to provide illumination while you fasten your seat belts or when you enter or exit the car. If one of these lights stops working, then it is time for some troubleshooting. Here are some tips to help you find out what could be causing the component to go bad.
Courtesy lights stop working after one use
If you have just replaced your courtesy lights with new bulbs but one or all of them stopped working after just one use, then it might be caused by the bulb itself. Check each bulb if they are of the right polarity. If at least one of them is not, simply discard them and replace with the suitable bulbs.
Courtesy lights remain dimly lit
Another common problem with the courtesy light kit is when it would not shut off but instead stays dimly lit. If your component is behaving this way, you will have to rewire its connection. Because this is an electrical problem, it might be better for you to take your car to an electrician. However, if you are confident with your skills, you might be able to fix it yourself.
Courtesy lights are not shutting off
Courtesy lights have a well-known function in which they turn off whenever you put the gear on "Drive" or whenever all the doors are locked. However, if you have this function activated but they remain lit all the time, then there might be something wrong with either the component itself or the door. Check if all the doors are really closed. If they are, then the courtesy light "Door" switch might be defective. It is also possible that the interior light electrical circuitry has shorted.
Other troubleshooting tips
Check the fuse box and look for a fuse labeled "Courtesy," "Interior," or "CTSY," to see if the component's fuse has blown.
It is also possible that the courtesy light switch is causing the problem. Test each of its function and see which one is not working.
Have one new bulb on hand that you will only use for testing. Should one courtesy light fail, remove the bulb from the bad component, replace it with the test bulb, and turn on the light. If the test bulb works, then the bulb you just removed is the problem.