Hooked Battery Up Backwards Now Car Won’t Start – All You Need To Know

The car won’t start after I hooked up the battery backwards? Due to their carelessness or lack of the required skills, some people replace or fix the battery on their own and make these errors. In the worst-case scenario, this mistake can end in many other issues, increasing the harm, and you may pay extra for third-party services.

What happens if you put the battery the wrong way? What can you do to solve it? You can find the solutions in the parts following this one.

Table of Contents

Will A Car Start If The Battery Is Backward?

By incorrectly putting the batteries, it is simple to blow the primary fuse in addition to other fuses. If the fuse blows, you won’t be able to start your car. 

Moreover, it might make the starter motor rotate in reverse. Also, this results in the starting system functioning, but the engine is not starting.

What Happens If You Install A Car Battery Backwards?

What happens if you install a car battery backwards? You will frequently face at least one of these general problems, if not all of them.

  • The circuit will be overloaded and might trigger the circuit breaker, halting the performance of
  • Once the charger’s capacity surpasses its capacity, the battery could overheat and burn with ejection.
  • The current flowing to the battery could harm the charger’s electrical systems.
  • Its circuit can be completely or partially damaged.
  • The circuit if the charger’s rating is less than the battery capacity.
  • The destroyed cover could enable acid to enter, destroying sensitive machinery and possibly generating major problems.
  • This could receive lasting damage or spark.

Hooked Jumper Cables Up Backwards Now Car Won’t Start

When the jumper cables were turned backwards, many events could have happened. For the vehicle to start, the battery cables directly can be damaged and need to be replaced.

Whereas the battery cables are the most probable reason, your car’s PCM or core computer may also have been harmed during the operation.

Hooked Battery Up Backwards – How To Fix?

Fusible links are a typical trait of old cars and aid in avoiding damage. It is a small wire with heavy insulation intended to break whenever the system receives an excessive amount of power. 

The thin wires, called fusible links, are positioned between layers with many electrical currents. Yet, if it exceeds its limit, this will cut off the electricity, and the car is intended to be safeguarded from catching fire by the strong insulation.

Hooked Battery Up Backwards

Fusible links need to be replaced if they have blown. The steps below can be used to replace the fusible link:

  • On the negative part of the battery, disconnect the terminal.
  • The fusible links should be cut on both sides with pliers.
  • Get the replacement fusible links, and then begin attaching them to the interiors of the wires and the surrounding wires.
  • To ensure the wires are properly linked, give them a thorough twist.
  • To confirm that the link remains in place, add a crimp.
  • A soldering iron can be employed to heat the connecting wire and tighten the connection.
  • Use a heat shrink tube, and wrap it around the overlapping wires.
  • Employing a heat gun, position the heat shrink tube.

Now that the fusible links have been properly changed, you are ready to go. If you don’t have access to the needed equipment, you can bring it to a mechanic, who can perform this task for you.

Dead battery

Generally, a dead car battery would be simple to identify because its contents would leak out and create a problem. If you start your car after the battery has been placed wrongly, it could be damaged. If your car won’t start because the battery is dead, it’s time to replace it.

Damaged ECU

The worst-case outcome of poorly linked car battery terminals is a destroyed ECU. It is rare, but an excessively large current flow could still destroy the ECU. If the damage isn’t too serious, repairing it can be successful. If not, you’ll have to replace it.

The cost of changing the ECU can run between $800 to $1500, based on your car. It should be inspected by trained mechanics who can tell you whether it can be repaired.

Fried Alternator

You’re in favor of the issue being resolved by changing blown fuses or repairing fusible links since no key engine part has been harmed. Yet, if the generated current is sufficient, it could fry the alternator even after the fuse has blown.

That will stop your car from starting. If the alternator has failed, it should be changed. It’s the easiest way to change, so you can handle it yourself if you’ve done it before. If not, bring it to a mechanic, who will change it for you.

The fuse must be the next point you check if replacing the battery doesn’t fix the problem. When you wrongly connect the negative and positive batteries to shield the other components from major damage, the most likely cause of the car not starting is a blown fuse. 

When the battery dies, the fuse which connects to it is blown. Many fuses connected to the battery are all either 80 amp or 100 amp fuses. If a fuse is blown, your car won’t start, no matter how much you use jumper cables to restart it.

You must replace a blown fusible link. These methods can be used to change the fusible link:

  • The two screws keeping the old fuse in position should be removed.
  • You can assess the two fuses’ sizes by placing one fuse on top of the other.
  • Mark the area where the new fuse should be cut with a tungsten pen.
  • To match the edges of the old fuses, employ scissors to cut the new fuse’s edges.
  • Create a hole in the new fuse.
  • Once again, confirm that the two fuses are compatible.
  • Put the new fuse in the fuse box.
  • Fasten the two screws firmly.

What Happens If Battery Is Charged With Reverse Polarity

As a result of the heat created by the battery’s reverse polarity, hydrogen gas which is highly combustible, leaks from the battery’s casing and creates an explosion. 

The acid that could destroy delicate devices and hurt people badly could enter the battery through the battery’s damaged cover.

How To Fix Reverse Polarity On A Car Battery

The best part is that you can easily fix reverse polarity on a battery without needing special tools or complex understanding. All you need to do is change the terminals on your cables with the corresponding battery terminals. 

To put it differently, connect the wire with only a positive terminal to the battery’s positive terminal and the opposite with a negative terminal to the negative terminal.

Your engine comes loaded with two distinct types of battery wires. One positive and one negative wire compose the two wires. The positive wire has a red or positive (+)-marked positive termination that is constructed into it. Inversely, the negative wire has a terminal that can be black or marked with a negative (-) indication.


What Fuse Blows When Jumping A Car?

The main fuse is the one that often blows when jumping a car. Any mechanical fault involving a motor or a moving component controlled by electricity could be the cause.

Can You Change The Polarity Of A Car Battery?

A lead acid battery needs external input to change its polarity. Simply put, it is impossible.

Can You Fix A Reverse Polarity Battery?

Discharge the battery entirely by connecting a low amp light bulb without using any cut-out circuitry.

Leave a Comment