How to Replace a Wire Terminal to a Car Battery

Replacing battery terminals to avoid starting problems

Over time the terminals on an automotive battery can become encrusted in corrosion. While this corrosion is normal and expected, if it is allowed to remain for too long it can interfere with the flow of current from the battery and cause starting problems. In some cases battery terminals become corroded or damaged beyond cleaning or repair. Common repairs involve simply replacing the terminal with a bolt-on unit, but that is not the best method available.

Things You'll Need

• Memory minder tool
• Box end wrench set
• Wire cutters
• Knife
• Battery terminal cleaning tool
• Wire brush
• Battery terminal crimping tool

Instructions

1. Plug the memory minder tool into the cigarette lighter socket if the vehicle was manufactured after 1996. Disconnect the negative cable from the battery with a box end wrench, then disconnect the positive cable.

2. Cut the wire directly at the terminal with the wire cutters and throw away the old terminal.

3. Carefully strip away approximately 3/4 inch of insulation from the end of the wire with the knife. Clean the bare wire with a wire brush until the bare wire is shiny to ensure that a good connection will be made.

4. Insert the bare end of the wire into the end of the new battery terminal.

5. Place the end of the terminal with the wire in it into the crimping tool, and compress the tool until the wire is solidly enclosed by the terminal.

6. Clean the terminals on the battery with the terminal cleaning tool by sliding the tool over the terminal posts and twisting the tool back and forth. The terminal is clean when it is shiny.

7. Replace the battery terminal onto the battery and tighten it firmly using the box end wrench.

8. Repeat the process to replace the other terminal, if necessary.

Tips & Warnings

• Vehicles manufactured after 1996 began using the OBD-II computer system. This system can be more difficult to reset if the battery is removed, so a "memory minder" tool is recommended for use anytime the battery is disconnected to preserve the system's memory settings.

• Always disconnect the negative battery terminal first. Disconnecting the positive cable first can result in sparks and short circuits.

References

• Agco: Replacing Battery Terminals
• OBD2: OBD-II Background