The 1989-1997 2.3L Ford Ranger (Mazda B2300) comes equipped with a fuel pump inertia switch.
In this article, I'll answer some of the most commonly asked questions about the fuel pump inertia switch.
Contents of this tutorial:
APPLIES TO: This tutorial applies to the following vehicles:
- 2.3L Ford Ranger: 1989, 1990, 1991, 1992, 1993,1994, 1995, 1996, 1997.
- 2.3L Mazda B2300: 1994, 1995, 1996, 1997.
The following tutorials will help you test the fuel pump:
- How To Test The Fuel Pump (1990-1994 2.3L Ford Ranger).
- How To Test The Fuel Pump (1995-1997 2.3L Ford Ranger).
What Is The Fuel Pump Inertia Switch Used For?
The purpose of the fuel pump inertia switch is to deactivate the fuel pump in the event your Ford Ranger experiences a sudden impact, such as a collision with another vehicle or vehicle rollover.
Shutting off power to the electric fuel pump under these circumstances prevents fuel from leaking all over the vehicle if the collision ruptured fuel lines, reducing the risk of a post-crash fire.
Unfortunately, a vehicle collision isn't the only thing that can trigger the fuel pump inertia switch. Here are a few other things that can trigger it:
- Hitting a curb.
- Hitting a large enough bump in the road.
- Hitting a big pothole.
- A tire blowout.
If a sudden impact activates the fuel pump inertia switch and you're still able to drive the vehicle, the engine will not start until the fuel pump inertia switch is reset and allows the fuel pump to get power.
How Do I Know If My Inertia Switch Is Tripped?
The most common symptom of a tripped fuel pump inertia switch is an engine no-start problem.
You'll also see that the fuel pump inertia switch reset button will be raised to its tripped position.
More specifically, when the inertia switch is tripped, you turn the key to start the engine, the engine only cranks but does not start.
The engine no-start problem is caused by the fuel pump inertia switch not allowing power from the fuel pump relay to get to the fuel pump.
If the fuel pump is not receiving power from the fuel pump relay, it will not supply fuel to the fuel injectors.
How Do I Reset The Fuel Pump Inertia Switch?
The fuel pump inertia switch has a button on top (see photo above). This is the reset button.
If a sudden impact has tripped the fuel pump inertia switch, the button will be raised (as seen in the photo above).
To reset the fuel pump inertia switch, press the button down. You'll feel a click as the switch resets and the button will now stay in a lower position (above the inertia switch assembly).
If the fuel pump inertia switch has tripped and is behind the engine no-start problem, resetting it will allow the engine to start.
IMPORTANT: In case of a collision, DO NOT reset the fuel pump inertia switch if you see or smell gasoline.
Where Is The Fuel Pump Inertia Switch Located?
|2.3L Ford Ranger|
|1989-1997||Below the instrument panel, to the right of the transmission hump.|
|2.3L Mazda B2300|
|1994-1997||Below the instrument panel, to the right of the transmission hump.|
More 2.3L Ford Ranger Tutorials
A full list of 2.3L Ford Ranger and Mazda B2300 tutorials can be found here:
Here's a sample of the tutorials you'll find:
- How To Test The Throttle Position Sensor (2.3L Ranger, Mustang, B2300).
- How To Test The Ignition Module And Crank Sensor (2.3L Ranger, Mustang, B2300).
- How To Test For A Blown Head Gasket (2.3L Ranger, Mustang, B2300).
- Testing The Blower Resistor (1995-1997 2.3L Ford Ranger).
If this info really saved the day, buy me a beer!