Can Jumper Cables go Bad (Causes + Fixes)?

Do you own a set of jumper cables that are not able to start your car or even charge the battery?

Are you wondering whether they are bad?

In this post, I go over whether:

  • jumper cables can go bad,
  • likely causes,
  • how you can test them

in addition to related questions such as what causes them to become hot and melt.

Can Jumper Cables go Bad?

Yes, Jumper cables can be damaged if they are made of poor quality materials or quality of manufacture is bad for example in the case of loosely fitted clamps.

Using undersized jumper cables also increases the risk of fire and melting of the jumper cables!

How Long Jumper Cables Last

A well-made set of jumper cables that are sized appropriately for the size of vehicles you need to start can last for many years.

Some people still have a working set of jumper cables that was purchased more than 5-7 years ago!

Larger vehicles – vans, trucks have a higher starting current, so heavy-duty jumper cables using thicker, lower gauge wire should be used.

They are usually made of thick wire, good insulation with strong sturdy clamps, and do not heat up as you use them to jump-start the car.

This combined with the fact that there are occasionally used can last for a very long time.

What Can go Bad with Jumper Cables?

There are several ways that your jumper cables can go bad: clamps falling off because they are not fixed firmly, undersized (thinner) cables for the size of the car that melt, or you receive a defective set.

Jumper cables may fail to work with your car. There are several possible reasons why this may be the case.

3 Reasons Why Jumper Cables Fail (+Solutions)

Jumper cables can go bad because of several reasons listed below.

Included are suggestions that can help prevent or minimize the risk of damage to your jumper cables.

Poor workmanship. Poorly made cables, loosely fitted clamps that do not make firm connections with the cables can cause your jumper cables to fail – clamps can fall off, the car can fail to start the car, heat up, and even melt.

Solution: Only buy jumper cables from a reputable supplier with genuine reviews.

Undersizing of the jumper cables – lower current rating compared to what is required.

Use jumper cables with the right wire gauge and current handling capacity suited to your car’s size.

You increase the risk of fire, damage to the car, and injury to yourself when you use cables of a lower current rating compared to what your car draws.

small gauge number means thicker cable, less resistance, and heating of the cable.

A 4-gauge is thicker than a 6 gauge jumper cable

Solution: 4-gauge or lower wire is generally a good starting size for jumper cables because it caters to small cars, pickup trucks, vans, and small trucks without getting hot.

You can not be sure which size of vehicle you will need to jump during an emergency, so it is better to be ready.

No through cable connections on one or both cables. Whereas the jumper cables are usually sturdy, in some cases you can have cables that cannot start the car or even charge the dead or weak battery because of a broken cable connection within the cables themselves.

Unfortunately, in some cases, this is only noticed when it is too late – when you need to jumpstart your vehicle and after the return period for your cables has expired. Whenever possible inspect and test your set of jumper cables first.

Poor connections between the clamps and the battery posts.

Sometimes, the car with a dead battery can fail to start even with a good set of jumper cables. When this happens:

  • check that the jumper cables connections have been made the right way, red on positive, and black on negative (chassis of the car with the dead battery)
  • Confirm that the jumper cable clamps are firmly connected to the battery posts

How to Test if Jumper Cables Work

Physical Inspection

To test jumper cables, first inspect them along the cable length for any damage to the insulation.

Confirm that the cable clamps are firmly fixed to each end of the cable.

If damaged, avoid using them as it increases the risk of a short-circuit and fire.

Cable clamps should be firmly connected to the end of the cables.

Continuity Test

You can then test each cable using a multimeter set to measure resistance, lowest resting, or set to the buzzer set.

Connect the probe wires of the multimeter to each end of the jumper wire, first red then black.

For a properly working cable, the multi-meter will read zero ohms or the continuity buzzer will sound too.

When to Replace Jumper Cables?

Related questions

1. What Causes Jumper Cables to get Hot?

A combination of the high starting currents drawn by the car at startup combined with cables that have a low current rating causes heat buildup in the cabling and melting of the insulation.

In severe cases, you may experience smoke and fire that can burn through the body of the car.

You can void the risk of smoke and fire when you use appropriately sized jumper cables.

6-gauge jumper cables can be a fire risk with larger cars.

If not sure, use the heavy-duty jumper cables with 4, 0, or 1 gauge especially when jumping the larger vehicles that have a significantly higher current draw.

2. Can you use Melted Jumper Cables?

No, avoid using melted jumper cables. The insulation is damaged and it is likely high resistance of the jumper wires that increase the risk of a short-circuit, fire, damage to the vehicle, and injury to yourself.

Final Thoughts

Whereas good quality jumper cables can last a long time, poor quality or undersized jumper cables can go bad, failing to work or smoking and possibly causing a fire.

Always buy good quality, well-regarded set of jumper cables. Best to use 4-gauge or lower to cater for jumping small cars, pickup trucks, vans, and small trucks without getting hot.

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