They can corrode so badly they won’t carry a current
Electric work can be daunting while restoring a classic car, and it can turn into a real headache. One easy check if you’re having difficulty getting any electrical power is seeing whether you need to replace a battery cable.
It seems like such a simple idea, but a corroded copper cable can fail to carry any current, which will obviously be a big problem — no ignition power, no radio, nothing. The problem is that battery cables are wrapped in insulation, which can make spotting corrosion difficult.
In the video above, Ron Francis Wiring owner and president Scott Bowers offers a tip for diagnosing a bad battery cable without cutting through the insulation.
“One little trick is, even though it’s kind of stiff, if you bend it in places, and if it’s stiffer in one area than the rest, there’s a pretty good chance that there’s something going on in there, like corrosion, that is stiffening up that area of the copper,” he says.
Bowers also pointed out that if a battery cable is 20 years old or older, it’s likely a good idea to just replace it. While you’re at it, you should replace both cables. It’s cheap and easy insurance.
That also would be a good time to increase the cable’s gauge — the bigger the gauge, the more current it can handle — to support any additional accessories that you might have added to the vehicle.