Ford F150 (1997-2004) Fuse Diagram • FuseCheck.com (2024)

FAQs

Where is the o2 sensor fuse on a 2004 Ford f150? ›

On the 2004 Ford Truck F-150 Heritage Pickup with the V6-4.2L engine, the fuse for the oxygen sensors is located in the under-hood fuse block. The fuse is # F1. 23. This is a 15amp fuse.

Why do O2 sensors fail? Since the oxygen sensor is in the exhaust stream, it can become contaminated. Common sources of contamination include an excessively rich fuel mixture condition or oil blow-by in an older engine and engine coolant being burnt in the combustion chamber as a result of an engine gasket leak.

Listening for a Clicking Sound

As the circuit is completed, the relay should make an audible click that indicates that the electromagnet is working and is completing the circuit. If the relay doesn't make an audible click, it might mean that the relay has stopped working and isn't completing the circuit.

Sometimes a fuse is bad but not necessarily blown. In this case, the best way to test it is with a test light or a multimeter. These are both relatively inexpensive tools and provide an easy way of checking if there's a current running through the fuse.

Open the fuse box and look at the glass containers that hold the fuses. If you can see that the fuse is visibly broken, or there is metallic residue on the glass from the fuse blowing, you will need to replace that particular fuse. Always turn your power off before replacing a fuse.

Engine fuse boxes are typically situated near the battery. In this vehicle, the battery is on the driver's side, and there is a fuse box right above it with a black plastic cover to protect the fuses. On the passenger side, there is also a battery, and the fuse box is located nearby.

The first thing to do is find your main fuse box (these days called a consumer unit), which will be in the same place as your electricity meter. They're often in the main hallway of a house, in a purpose-built cupboard.

Your fuse box will have two sets of fuses. At the bottom will be 15-amp and 20-amp screw-in fuses with glass faces that are exposed and visible. These fuses will service branch light circuits and outlet circuits. At the top will be 30-amp or 40-amp cartridge main fuses for ovens, laundry rooms, or stoves.

If you're using a digital multimeter set to measure resistance, touch the probes together to get an initial reading. Then put the probes on either side of the fuse and check if the reading is similar. If it is, then the fuse works properly. If you get no reading or “OL”, then the fuse has blown.

Is there a relay for O2 sensor? ›

The O₂ sensor's heater circuit is controlled in one of two ways. First is the positively controlled type of circuit. If the O₂ sensor heater circuit's negative wire goes directly to ground, look for a short-to-power problem. Usually the heater circuit in this case is controlled by a relay.

To answer your question, there is no fuse for the coolant temperature sensor, it is connected directly to the vehicle ECM. The ECM supplies a supply voltage on one wire, and the other wire is the signal wire returning to the ECM .

The oxygen or lambda sensor in a properly functioning exhaust system monitors the A/F ratio, as often as one hundred times per second, and reports this information to the vehicle's ECU or engine control unit (also referred to as the PCM or ECM).