2007 Peterbilt 387 Fuse Box Diagram (2024)

FAQs

Where is the brake light switch on a 2007 Peterbilt 387? ›

The brake light switch is air operated and located under the cab driver side on the air brake valve.

The two most common symptoms are: An overloaded circuit which will blow the fuses in question. As a result, this will cause any associated devices to disconnect. Lastly, the smell of burning is another clear indication of a faulty fuse, as well as the smell you will notice burn marks on the fuse box.

The first thing to check is whether or not the brake light fuse has blown. This fuse is usually located in the fuse box under the hood, and it's relatively easy to check. Just remove the fuse and hold it up to a light - if the wire inside is broken, then you'll need to replace the fuse.

Normally, the simplest way to check whether or not your brake light switch is working is to observe the brake lights when you apply the brakes. If the brake lights don't come on or work intermittently, there's a good chance the brake light switch is faulty. Check the fuse.

Remove the fuse from its holder. In some cases you may need a small screwdriver to unscrew the fuse holder cap. Look at the fuse wire. If there is a visible gap in the wire or a dark or metallic smear inside the glass then the fuse is blown and needs to be replaced.

Locating the Fuse Box

In most cases, the main fuse box is situated under the hood, near the battery, while secondary panels can be found in the passenger compartment, often hidden behind a removable panel.

The car's electrical system all runs through the fuse boxes. You can replace a blown fuse but if the blown fuse is bad enough, some of the wiring might be damaged. This can prevent cars from starting. You can find the map to your vehicle's fuse box in the owners manual.

You can see your brake light switch by looking under the dash, near the top of the brake pedal. The brake light switch is usually attached to a small bracket that holds the switch, activated when the pedal is depressed, in position.

If you have a step-on parking brake, this switch is located underneath the dash. On the other hand, if you have a hand-style parking brake, you can find this switch under the center console assembly.

12 – Stop Light Switch. Drivers behind you must be warned when you put your brakes on. The air brake system does this with an electric switch that works by air pressure. The switch turns on the brake lights when you put on the air brakes.

What presses the brake light switch? ›

When the foot is removed from the brake pedal, the upward force of the brake pedal pushes the spring of the brake switch back, causing the contacts to open, that is, the signal to be cut off.