1. Autos
Bulbs and Fuses
Every car has them but a lot of people don't understand how much they mean for safety and how easy they are to replace.
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Part 1: Headlights
• Part 2: T/S and Brake Lights
Part 3: Fuses
 
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Turn Signal And Brake Light Bulbs

Turn signal and brake light bulbs are standard for all makes and models of cars with a few variations. The two most common bulbs are the 1157 and 1156 bulbs. The 1157 is usually used in applications where brake light and turn signals share the same bulbs and the 1156 is use for single purpose jobs.

The 1157 is a dual filament bulb while the 1156 is a single filament bulb. They look very similar but are not interchangeable. A common mistake is to put an 1156 into a socket for an 1157 bulb. This causes all kinds of weird problems like dash lights going on when you step on the brake. You can see in the pictures below that the 1157 has two brass terminals in the base while the 1156 has only one. The 1157 bulb is also keyed so it will only go into the socket one way. Note that one lock tab on the 1157 is higher than the other. This prevents it from going in wrong. Also note that the lock tabs on the 1156 are the same height so it will not go into an 1157 socket.

These bulbs also come in a bayonet style bulb and are keyed as well to prevent them from being inserted incorrectly.

To remove the round based bulbs you simply push the bulb in and turn it counter clockwise. On bayonet type bulbs there is a plastic tab that locks the bulb in. To remove these just use a small screwdriver to unlock the tab and pull the bulb out. It would be a good idea to wear gloves to protect your fingers should the bulb break. Replacing these bulbs is simple.

Sometimes the hardest part is getting to the sockets that hold the bulb. For most front turn signal bulbs and marker lights, it's just a matter of removing two screws from the lens, taking off the lens and removing the bulb. On some cars you can reach behind the light assembly and twist the whole socket assembly out and then replace the bulb. Marker lights are similar to the turn signals except most use a 197 bayonet type bulb.


Typical 1156 bulb

Typical 1157 bulb


Typical bayonet type bulb

In the back most tail light bulbs are accessible from inside the trunk. Some cars have a cover you remove to gain access to the sockets. Some cars have large plastic thumb type nuts that you remove and take the whole tail light assembly out. Other types have screws going through the lens assembly that you need to remove. These assemblies have all the bulbs for the rear in them. Back up, turn signal and brake light bulbs are all part of it.

Hatchbacks, wagons and pick-ups usually have access panels in the corners to let you get at the sockets or mounting screws. Most have the screws through the lens to replace bulbs.

This is where you have to be a little careful with the bulbs since 1156 and 1157 bulbs, and other types, are used back there. Depending on what type your car has, changing the bulbs is very similar to the front. Either twist the socket out and replace the bulb or twist the bulb out.

One place where you will run into the most problems is the Center Mount Stop Light (CMSL). Most are mounted inside the car on the rear deck lid. Removing these can be a problem. Some have mounting screws hidden by small plastic covers. Some have studs extending down into the trunk and are held in with small nuts. This requires you go into the trunk, remove the nuts and lift the whole assembly out. Some simply snap into place and can be difficult to remove if you don't know where the lock tabs are.

License plate lights are usually fairly simple to replace. Most simply have two screws, similar to the front, that go through the lens to gain access to the bulbs.

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