The inertia switch is a safety feature in Ford F150 to shut off the power supply to the fuel pump in a collision or road accident to prevent fire hazards.
How Do I Bypass the Inertia Switch on a Ford F150? Bypassing the inertia switch on Ford F-150 is straightforward, and you need to twist the in and out wire of the switch together. Another way is to install a jumper to short the terminals of the inertia switch connector. The latest models have a software configured pump shutoff module that requires its settings from the software to bypass it.
However, it becomes a source of inconvenience sometimes due to its erroneous activation due to road jerks, and you won’t be able to figure out the fault.
Therefore, bypassing the switch is a temporary remedial measure to keep your journey going until replacing the inertia switch.
How Do I Bypass the Inertia Switch on a Ford F150?
This article will discuss the procedure to bypass the fuel pump-shutoff inertia switch in Ford F-150 trucks, its pros, and cons.
Wiring of inertia switch
Fuel pump inertia switch has typically closed contacts and cuts off the power supply to the fuel pump relay on a solid jerk.
It has simple wiring consisting of a single wire from the fuel pump module in PCM at its input and an output wire to the pump relay.
It is a mechanically operated switch and disconnects the power supply to the pump whenever activated.
The color code of the wire can be dark green/yellow in earlier models and pink/black in later trucks.
However, it can vary according to the model and switch purchased for replacing the original one.
The third wire in some switches works as a safety signal to inform the fuel pump module about the activation of the switch after an accident or collision.
Steps to bypass the fuel pump inertia switch
It is a simple task as you have to make a direct connection of power from the pump module to the pump relay.
Here are 3 easy steps to bypass the inertia switch if it prevents the pump from starting due to malfunctioning. Another reason can be the failure to reset it.
Locate the switch
The first step is to locate the switch before bypassing it. You will find it installed over the firewall on the passenger side installed on the floor in earlier pickup trucks.
Find it by lifting the front corner of the floor mat where passengers’ feet rest.
New models of Ford F150 have an inertia switch under the corner panel on the passenger side near the door frame. You will find it under the fuel pump driver module.
It has a pretty simple shape and size of a matchbox fixed with the help of screws.
You can quickly identify it by its black-colored body and a round-shaped red pushbutton on top of it. In case of activation, you will find the red button popped out. Press it or push it back to reset the switch.
Remove the wires from the switch
The fuel pump module provides the power supply to its module via passing through the switch.
So, first, pull both wires out of the switch. You can do it by removing the connector to the switch or cutting both wires before the connector.
Short both switch terminals
The third and last step is directly powering up the fuel pump relay. Simply connect the 2 wires.
Another way is to insert a jumper wire between both contacts of the switch connector. It will short out both contacts and directly provide power to the fuel pump.
Use software to bypass the inertia switch in the New Ford F150
Due to frequent false activation of inertia switch on bumpy roads, Ford has introduced the fuel pump shutoff feature in the latest models after 2000.
Therefore, you will not find the typical red button switch in these pickups. Instead, they have a fuel pump and supply cut-off feature integrated with the PCM of the truck.
Whenever a moderate to severe level crash occurs beyond the preset threshold, the restraint control module (RCM) sends a signal to the body control module (BCM).
BCM further sends an alert to a dedicated circuit in PCM that acknowledges it and sends the fuel pump shutoff signal disabling its relay.
To reset the shutoff signal, turn the ignition switch to OFF and then ON position. Sometimes, you have to repeat it to start the truck. If there is a Start/Stop button for ignition, press the button twice to reset the feature.
Bypassing this feature requires hacking the PCM using the Forscan software tool and OBD adapter.
However, it is a software-enabled feature, and you need to disable it from there by applying specific bypass codes available.
Do all Ford F150 trucks have inertia shutoff switches?
Ford introduced an inertia shutoff switch in the initial racing car model to cut off the fuel supply in an accident to avoid fire risk.
However, later on, it became a standard safety feature for all vehicles, including Ford F-150 trucks. Owners using trucks for off-road applications bypass it as it frequently trips on bumpy tracks or rough terrains.
But they have replaced it with an integrated fuel pump shutoff mechanism with PCM.
Moreover, this new feature is more accurate and activates due to collision above the calibrated threshold level.
Furthermore, a restraint control module linked with airbags coordinates with BCM and PCM to send a shutoff signal to the fuel pump relay module.
There are few disadvantages of bypassing the inertia switch on your Ford F-150 truck.
Risk of Fire
Bypassing it is not a great deal technically; however, it puts you, your family, and your truck at risk, and your truck can catch on fire.
I have witnessed several road accidents where this safety feature activated and saved lives and property by cutting off the fuel supply.
Therefore, if you feel the inconvenience of frequent stoppage of fuel pump due to a faulty switch, get it replaced with a new one. It will cost around $40-$120, depending on the model and quality of the switch.
Unable to Turn Fuel Supply during Maintenance Work
Moreover, the inertia switch serves to turn off the fuel while doing maintenance work on Ford F-150 or parking for a longer duration.
If you bypass it, any erroneous voltage from the battery will turn ON the fuel pump resulting in fuel leakage.
Loss of Warranty and Insurance
If you bypass the fuel pump shutoff feature using a software hack, it will void the warranty by the company.
Furthermore, as it is a safety feature, bypassing it will also cause you to lose your insurance.
Therefore, in the best interest of you and your truck’s safety, it is a recommended solution to replace the faulty switch instead of bypassing it.