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2009-2013 Mazda3 Fusebox Terminal Decorrosion Repair

If your 2009-2013 Mazda3 is experiencing...

iFixit Library 2009-2013 Mazda 3 Very easy 1 - 10 minutes Guide 209860

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This attributed iFixit guide is displayed through Fixonic's recorded commercial API permission. iFixit remains the independent source and author of the procedure.

Guide overview

Before you begin

If your 2009-2013 Mazda3 is experiencing intermittent power cuts to all electrical systems in the vehicle, and the battery connections are not the culprit, use this guide to reseat and connection in the fuse box terminal.The fusebox terminal is responsible for delivering power from the battery to all electrical systems in the car. If the connection is bad, the power may cut intermittently or permanently until the connection is restored.Before using this guide, ensure that the battery itself has been charged, and use a multimeter to check if the battery terminals have a good connection.Step one of this guide will show you how to disconnect the battery. It is very important that this step is not ignored.

Step 1

Repair step

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TOOL USED ON THIS STEP Flathead 3/32" or 2.5 mm Screwdriver Referenced by the iFixit guide

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Remove the battery cover box by lifting at the seam.
Using a 10mm wrench (or socket, if you have one that fits), remove the negative (black or green) battery terminal by unscrewing the connecting nut.
You don't have to remove it all the way, just loosen it so the terminal can slide off the battery.
Do the same as above, but with the positive (red) terminal.
When removing the terminals, make sure to position them aside where they won't slide into the posts you removed them from. I recommend putting them on the driver's side of the battery, between it and the wall.

Step 2

Repair step

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TOOL USED ON THIS STEP Flathead 3/32" or 2.5 mm Screwdriver Referenced by the iFixit guide

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Remove the fusebox cover by pressing the tab on the cabin-side of the fusebox and lifting.
Use a 10mm wrench or socket to loosen the bolt. Once tension is broken, you can twist by hand.
Use a screwdriver or any similar item to wedge underneath the connector and pull it up off of the post. Hooked tools work even better.
Leave the screwdriver underneath the terminal to keep it from falling back on.
Be careful when using the wrench and screwdrivers to avoid hitting any of the fuses inside the fusebox.

Step 3

Repair step

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Using contact cleaner or a very fine sandpaper, clean off the corrosion on the post.
Repeat the cleaning process for both the underside and the topside of the terminal connector.
When using sandpaper, it's important to be gentle with the cleaning process to avoid deeply scratching the connector or grinding off protective coatings.
There is no corrosion on the pictures provided, as I had already conducted the repair a week prior. The grease that can be seen is a result from that as well.

Step 4

Repair step

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TOOL USED ON THIS STEP Gloves Referenced by the iFixit guide

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Add a very small amount of dielectric grease to either your fingertip (if you're wearing gloves) or another tool that you can use to apply the paste without scratching the surfaces.
Apply a thin layer of the grease to the base of the terminal connection post, where the metal square is.
Apply a thin layer of the grease to the underside of the terminal connector.
Dielectric grease can cause skin and eye irritation, so avoiding direct contact is recommended.

Step 5

Repair step

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TOOL USED ON THIS STEP Flathead 3/32" or 2.5 mm Screwdriver Referenced by the iFixit guide

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Use the screwdriver (or other tool used to hold the connection away) to move the terminal connector back onto the post.
Hand-twist the nut back onto the terminal connection post.
Use a 10mm wrench (or socket) to tighten the nut fully.
It is a good idea to make sure that it is firmly tightened, but you do not need to make it much tighter than when it wants to stop rotating.

Step 6

Repair step

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Reconnect the battery positive terminal to the positive battery post. Tighten the nut with a 10mm wrench or socket.
Reconnect the negative terminal to the negative battery post. Tighten the nut with a 10mm wrench or socket.
It is very important you connect the positive terminal before the negative terminal.
Make sure the nuts are tightened so that bumps will not cause the terminals to slide off the battery posts.

Step 7

Repair step

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Replace the fusebox cover, pushing down on the top close to the tab to ensure it clicks into place.
Replace the battery cover.