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Disconnecting 2000 Ford Focus

My husband’s 2000 Ford focus is not starting but when we can start it up we can only drive it for a few minutes before it will quit again. The battery is corroded so we want to replace it but are unsure of what it will do to the car if it’s disconnected. Can anyone help us know what to expect and how we should disconnect it?

I think you are better off just letting a good shop do that. The extra charge for the installation is modest and you can then be sure it was done properly.

Before cars had computers I did all this myself and used baking soda to clean the terminals.

You may also need an new cable in view of the fact the car is 15 years old and the cable is “corroded”.

Good luck!

Auto parts stores will change the battery FOR you if you buy the battery there and recycle the old one. They likely won’t clean the terminals and they definitely won’t change the cables, if needed.

Unhooking the battery won’t hurt anything in the car. The worst that can happen is you will lose your pre-set radio stations.

Walmart has a car shop. Some might call it a service center.

I use to plug this in cigarette lighters in vehicles before disconnecting the battery because customers would be angry that the pre-sets on the radio would be lost.

But on vehicles now, disconnecting the battery can result in it being towed to the dealer just to get it to start again.


It’s best to keep the computer powered up if possible during a battery change-out. But if you want to do the replacement yourself, drop by a Ford dealership shop and ask if you actually need to do that or not. If all that gets lost is the radio presets, that’s not a big problem. Some cars are more sensitive to this than others, and the Ford dealership shop should be able to tell you how this applies to your Ford.

Unless there’s some reason you prefer to do this yourself, it is probably easier to let a shop do it for you. A good shop will have the necessary equipment to keep the ECM powered up during the battery change.

BTW, if the battery is less than 3 year old, suggest to have it load tested first. Just b/c the terminals are corroded doesn’t imply it is no good. You may just need to have the terminals cleaned is all. That would certainly explain a no-crank. For the problem where it dies after running, that’s harder to say.

My wife once owned a vehicle with a radio that died when I changed the battery. What did I do? I bought her a better radio and used the dead one for target practice. It’s a dumb idea just because a thief might steal it someday. Sheesh!