Understanding Common Electrical Issues for Classic Cars

Understanding Common Electrical Issues for Classic Cars

Posted by Anderson Restoration Parts on 7th Oct 2022

At Andersen Restoration Parts, we're proud to serve as your one-stop shop for all the parts and accessories you may need for any kind of classic car restoration or repair. We serve clients who own a huge variety of different classic cars, and we pride ourselves in being able to provide not only parts, but also expertise to all of our clientele. Whether you need a suspension rebuild kit, a control arm set, a front-end rebuild kit or any other restoration product, we've got what you're looking for.

One particular type of issue that classic car owners need to be cognizant of on a regular basis: Electrical problems. Why are these more common in classic cars than other vehicles on average, and what are some of the most common electrical issues you should be keeping an eye out for within any classic car you own? Here's a rundown.

Why Do Classic Cars Have More Electrical Issues?

Firstly, let's dispel a common myth: Classic cars don't have more electrical issues simply because they're old. Rather, the reason that electrical issues seem more common in classic cars has to do with how they were built in the first place.

Older cars tended to be built with less-reliable components, and while this was partially due to technological limitations of the time, it was also due to the fact that cars were not expected to last as long as they do now. With that in mind, it's no surprise that electrical issues are more common in classic cars than in their modern counterparts - but that doesn't mean you're powerless to do anything about it.

Our next several sections will go over common such issues, plus what can typically be done about them.

Battery Cable Problems

For many classic car owners, the first sign that there may be an electrical issue present is battery cable problems. If you notice that your car's battery isn't holding a charge as well as it used to, or if the cables themselves are visibly frayed or damaged, it's important to take action immediately.

In many cases, simply replacing the damaged battery cables will be enough to do the trick. However, it's also possible that the problem lies deeper - in which case, you may need to consult with a professional mechanic to get to the bottom of things.

Alternator Problems

Another common electrical issue found in classic cars is alternator problems. The alternator is responsible for charging the battery while the car is running, so if you notice that your car's battery is dying more quickly than usual, it may be a sign that the alternator isn't doing its job correctly.

There are a few different ways to test whether or not your alternator is the issue. One is to simply turn on all of the car's accessories (lights, radio, etc.) and then start the car - if the car's battery dies quickly, it's likely that the alternator is the problem. Another way to test is to take a voltmeter and check the voltage of the battery while the car is running - if it's lower than 12 volts, that's another sign that there may be an issue with the alternator.

In either case, it's best to consult with a professional mechanic to get to the bottom of the problem and determine the best course of action.

Parasitic Draw

When we talk about an electrical "draw," what we're referring to is the amount of current (amperes) that are being pulled from the battery while the car is turned off. In most cases, a very small amount of current - less than 50 milliamps - is normal. However, if you notice that there's a higher draw present even when the car is turned off, it could be a sign of a parasitic draw - which, in turn, could be caused by a number of different issues, from a faulty alternator to a short circuit somewhere in the electrical system.

To test for a parasitic draw, you'll need to use an ammeter - simply disconnect the negative battery cable, connect the ammeter in line, and then reconnect the negative battery cable. If there's more than 50 milliamps of current present, that's a sign of a parasitic draw, and you'll need to consult with a professional mechanic to get to the bottom of it.


As any classic car owner knows, fuses are an important part of the electrical system, and they can be one of the first places to look when troubleshooting an electrical issue. If a particular circuit isn't working correctly, it's possible that a fuse has blown - in which case, simply replacing the fuse will generally do the trick.

Of course, it's also possible that there's another issue present - such as a short circuit - so if you find that you're constantly blowing fuses, it's best to consult with a professional mechanic to get to the bottom of the problem.

As we've seen, there are a number of different electrical issues that can afflict classic cars. However, in most cases, these issues can be resolved relatively easily - as long as you know what to look for. With this information in hand, you'll be well on your way to keeping your classic car in tip-top shape for years to come.

For more on this, or to learn about any of our wide selection of classic car restoration parts, speak to our team at Andersen Restoration Parts today.