Fuses and fusible links — general information Ford F150
Fuses
1. The electrical circuits of the vehicle are protected by a combination of fuses, circuit breakers and fusible links. Fuse blocks are located under the instrument panel and in the engine compartment (see illustrations).
.1a The engine compartment fuse/relay box is mounted to the top of the right inner fenderwell in the engine compartment — it contains miniaturized fuses, cartridge-type fusible links, relays and circuit breakers
.1b Remove the access panel from the right kick panel…
.1c… then remove the fuse box cover to gain access to the fuses in the BCM
2. Each of the fuses is designed to protect a specific circuit (or circuits), and the various circuits are identified on the fuse panel cover.
3. Miniaturized fuses are employed in the fuse blocks. These compact fuses, with blade terminal design, allow fingertip removal and replacement. If an electrical component fails, always check the fuse first. The best way to check a fuse is with a test light. Check for power at the exposed terminal tips of each fuse. If power is present on one side of the fuse but not the other, the fuse is blown. A blown fuse can also be confirmed by visually inspecting it (see illustration).
.3 When a fuse blows, the element between the terminals melts — the fuse on the left is blown, the fuse on the right is good
4. Be sure to replace blown fuses with the correct type. Fuses of different ratings are physically interchangeable, but only fuses of the proper rating should be used. Replacing a fuse with one of a higher or lower value than specified is not recommended. Each electrical circuit needs a specific amount of protection. The amperage value of each fuse is molded into the fuse body.
5. If the replacement fuse immediately fails, don’t replace it again until the cause of the problem is isolated and corrected. In most cases, this will be a short circuit in the wiring caused by a broken or deteriorated wire.
Caution: Avoid cheap knock-off fuses! Some aftermarket fuses can damage your electrical system. The actual fuse amperage does not match the amperage rating embossed into them. For example, a fuse marked as a 10 amp fuse may not blow until it reaches 30 amps of electrical load. As of the date of this manual publication, it is still very easy to tell these knock-off fuses from a good quality fuse. Look at the amperage number stamped into the fuse. The number should be filled in with a white or black paint. If the amperage rating is not filled in with paint but is only stamped into the fuse it IS a knock-off fuse and should NOT be installed in your vehicle. Severe and permanent electrical damage will occur to your vehicle.
Fusible links
6. Some circuits are protected by fusible links. The links are used in circuits which are not ordinarily fused, or which carry high current.
7. Cartridge type fusible links are located in the engine compartment fuse and relay box and are similar to a large fuse. After disconnecting the negative battery cable, simply unplug and replace a fusible link with one of the same amperage.