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Inertia Switch Explained Removed and Replaced 98-12 Ford Ranger

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  1. step : Resetting the Inertia Switch (1:42)
    • Locate the switch along the fire wall near the passenger floor
    • Press the button to turn the fuel pump on
  2. step : Removing the Inertia Switch (3:11)
    • Disconnect the connector with a flat blade screwdriver
    • Remove the two 5.5mm bolts from the switch
    • Remove the switch
  3. step : Installing the Inertia Switch (3:39)
    • Insert the inertia switch
    • Tighten the 5.5mm bolts by hand
    • Tighten the 5.5mm bolts
    • Connect the connector with a flat blade screwdriver

Hi, I'm Mike from 1AAuto. We've been selling auto parts for over 30 years! We're dedicated to delivering quality auto parts, expert customer service, and fast and free shipping, all backed by our 100% satisfaction guarantee. We've created thousands of videos to help you install our parts with confidence. That saves you time and money, so visit us at, your trusted source for quality auto parts.

In this video, we're going to be working with our 2001 Ford Ranger, but we're going to be talking to you about a very generic and common problem on Ford, Lincoln and Mercury vehicles.

Today we'll be talking about your inertia switch. This is designed to trip in the event of a collision with the vehicle, shutting off the fuel pump relay and preventing fuel flow from coming out of the vehicle. This is designed as a safety feature, so if your vehicle is ever in a collision which causes a fire, it won't literally fuel that fire by pumping more gas out of the tank.

However, these switches do tend to be troublesome. They're known to go off for bad suspension, shopping carts hitting vehicles, and other situations that create just the right vibration to set these off and prevent your vehicle from starting or, in certain cases like having a bad strut or shock that creates a jarring vibration when going over a big bump, the vehicle can even shut down while running. Fortunately, this is very simple to check and correct, and we're going to show you how.

The inertia switch on this particular truck is located up against the firewall on the passenger floor, right above where your passenger's right toes would be. At the very top here is a little red button. When you push it down, you'll see the red bar here, indicating that the switch is down and allowing the fuel pump to turn on. If this switch is popped up, you won't see the indicator inside of this window, and you'll feel it flush at the top here. This means that it's been tripped by something. Either something running into the side of the vehicle, maybe your vehicle was bumped while parked or hit with a shopping cart or something similar, or maybe you hit a hard bump and tripped it. Pushing it down will restore operation to the fuel pump and allow your vehicle to start normally again.

Now, fortunately it's easy to reset that switch, but you may still have an underlying issue, like a bad shock or strut or another suspension component like a bushing creating that jarring vibration that's causing this switch to trip. If you go through and everything seems normal and it seems like the switch is resetting itself too easily, you may have to change it out, and this is how.

Fold down the carpet where the inertia switch is, and remove the connector with the help of a flat blade screwdriver. Remove the two five and a half millimeter screws securing the switch to the firewall with a socket, ratchet and extension. Then remove your inertia switch from the vehicle.

Install the switch back onto the firewall, and start your two five and a half millimeter screws by hand. Then tighten the screws down with your socket and ratchet. Reconnect the electrical connector. Push your carpet back into place and you're good to go.

Thanks for watching. Visit us at for quality auto parts, fast and free shipping, and the best customer service in the industry.

Tools needed for replacement:

    Ratchets & Related

  • Ratchet

  • Screwdrivers & Related

  • Flat Blade Screwdriver

  • Sockets - Metric

  • 5.5mm Socket

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