Replacing A Car Battery Ground

The most important electrical connection in your car, if there is such a thing, is the ground. The ground is the heavy cable, normally color coded black, that attaches to the negative terminal of the battery. Anytime you are doing car work that involves electrical components, you should disconnect the ground cable from the battery first. With the ground removed, there is no way an electrical circuit can be completed by accident. The picture to the right shows a solid looking ground connector attached to the negative terminal of the battery. But I thought the starter cranked slow and saw a little discoloration on the plastic cover of the battery, so I went ahead and removed the connector. I should point out that I replaced both battery connectors around five years ago.

It turns out that the lead casting of the connector had partially melted and broken. While the nut that is cast into the connector was still in place, it no longer held the battery cable tightly because of the damage. You can see that the conductors had pulled out a little, which reduces the amount of contact area, increasing the electrical resistance and the heat generated. So did the cable pull out first or did the connector melt first? In any case, The first video to the lower left shows how to remove the old battery connector. I didn’t like the look of the copper conductors that had previously been exposed, so I checked that the ground cables were long enough and then cut them back for a clean area. The video below demonstrates cleanly stripping the heavy cable with a razor blade held in visegrips. I don’t recommend this method, it’s just that I loaned somebody my knife, so I didn’t have a choice!

I thought I’d just show the new connector alongside the older failed connector to the right. The photo below shows both ground cables stripped back for installation into the new connector. The larger of the two cables is the engine ground, while the smaller cable is bolted directly to the sidewall of the engine compartment. Both cables are installed in the same connector, as shown in the final video. I went ahead and taped up the cables after installing the battery connector, just to keep out the elements. It’s not an electrical insulation issue, all the metal on the car is at the same electrical potential, ie, ground. Finally, I tightened up the clamp nuts on the cable connector after installing the connector on the battery terminal. It’s just easier to do it with the connector firmly held in place rather than holding it in your hand.

If It Jams Home | The Omni Project | The Rusted Unibody | Cutting the Subframe | Cutting Out Rust | Building a Unibody | Bolt Together | Floor Replacement | Replacing Inner Tie Rod | Replacing Emergency Brake Cable | Replacing Battery Ground | Replacing Car Exhaust | Make a Shift Rod Bushing | Bosch Solenoid Rebuild | Contact