One of the most important safety devices on your 3.0L V6 Ford Ranger is the 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:
- 3.0L Ford Ranger: 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008.
- 3.0L Mazda B2300: 1994, 1996, 1997, 1998, 1999, 2001, 2002, 2003, 2004, 2005, 2006.
The following tutorials will help you test the fuel pump:
- How To Test The Fuel Pump (1991-1994 3.0L V6 Ford Ranger).
- How To Test The Fuel Pump (1995-1997 3.0L V6 Ford Ranger).
- How To Test The Fuel Pump (1998-2001 3.0L V6 Ford Ranger).
What Is The Fuel Pump Inertia Switch Used For?
The function of the fuel pump inertia switch is to cut off power to the fuel pump in the event that your Ford Ranger suffers a sudden impact, for example getting hit by another vehicle or experiencing a vehicle rollover.
Turning off power to the electric fuel pump under these circumstances will prevent fuel from being sprayed over the vehicle if the fuel lines are ruptured by the collision, reducing the risk of a post-impact fire.
Unfortunately, quite a few things other than a vehicle collision can trigger the inertial 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?
A tripped fuel pump inertia switch will cause an engine no-start problem. You'll also see the reset button move to the 'tripped' position.
Here are a few more details: The engine no-start issue is a result of the fuel pump inertia switch not allowing 12 Volts from the fuel pump relay to reach the fuel pump.
Without this voltage, the fuel pump will not operate and will not deliver fuel to the injectors. The result is an engine that cranks but won't start.
How Do I Reset The Fuel Pump Inertia Switch?
The fuel pump inertia switch has a reset button located on top of its assembly (see photo above).
If the button is raised (as seen in the photo above), you can conclude that the inertia switch was triggered by a sudden vehicle impact.
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 the engine will not start, resetting it should allow the engine to restart.
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?
| 3.0L Ford Ranger | |
|---|---|
| Year | Location |
| 1991-1997 | Below the instrument panel, to the right of the transmission hump. |
| 1998-2008 | Below right side of instrument panel, in right side kick panel area. |
| 3.0L Mazda B3000 | |
|---|---|
| Year | Location |
| 1994-1997 | Below the instrument panel, to the right of the transmission hump. |
| 1998-2008 | Below right side of instrument panel, in right side kick panel area. |
More 3.0L Ford Ranger Tutorials
You can find a complete list of tutorials here:
Here's a sample of the tutorials you'll find there:
- How To Test The Engine Compression (1991-2008 3.0L Ford Ranger).
- How To Test The Blower Motor (1998-2000 3.0L Ford Ranger).
- How To Test The Fuel Pump (1991-1994 3.0L V6 Ford Ranger) .
- How To Test The MAF Sensor (1998-2001 3.0L V6 Ford Ranger).
If this info saved the day, buy me a beer!
