What is the Function of Ignition Switch? | What are the Symptoms of Bad Ignition Switch?

The ignition switch is a major component of your vehicle. It is most commonly found in many trucks and cars. The ignition coil is typically located just behind the ignition lock cylinder on the steering column. When you insert the ignition key into the ignition switch and turn it, your vehicle engine starts. The ignition switch plays a major role in supplying the power from the vehicle battery to other electrical parts. This article mainly explains the bad ignition switch causes, symptoms, and replacement cost.

What is the Ignition Switch?

The ignition switch is an assembly that contains the ignition lock cylinder. The ignition switch has the responsibility of starting the car and powering certain parts of the car, such as the electronic parts, ignition, and engine.

Because the ignition switch delivers the electrical power to the vehicle’s electrical accessories, it is important to keep it in good working order throughout the life of the vehicle.

ignition switch

What does an ignition switch do?

The ignition switch of your vehicle is very important to keep it moving. It plays a crucial role in booting up the car’s main electrical system. If the ignition system does not work, the car may not start, or the power or radio windows may not work.

Like most car switches, a key is used to operate the ignition switch. You can start your car by putting and turning the key in the ignition switch. However, the latest car models have an ignition button instead of a key.

Symptoms Of a Bad Ignition Switch

As the ignition switch goes bad, it produces one of the below-given symptoms:

  1. Car Engine Won’t Start
  2. Ignition is constantly turned On
  3. Car stalls while driving
  4. Stuck steering wheel
  5. Hard to turn the key
  6. Silent starter motor
  7. Car starts and then suddenly stalls
  8. Issues powering on the accessories

1) Car Engine Won’t Start

The main function of the ignition switch is to help to start the vehicle. If your ignition switch goes bad, your vehicle engine won’t start. A faulty ignition switch will not properly supply power to the ignition system, starter motor, and other engine controls, causing the engine not to start.

However, many other electrical and mechanical issues (i.e., a dead battery) may also stop the vehicle engine from starting. In fact, it is recommended to contact a mechanic for the proper diagnosis.

2) Car stalls while driving

If your vehicle stalls suddenly while driving, it is one of the common symptoms of a bad ignition switch. When the ignition switch goes bad while the engine is running, power to the ignition system and fuel system will be lost, which may lead to the engine stalling. Depending on the specific problem, your car may or may not restart after a short time.

3) Hard to turn the key

Modern vehicle models use an ignition button instead of a key. If your car is still using a key and it does not turn smoothly whenever you try to start the vehicle, it means that there is something wrong. In such conditions, your ignition key may also get stuck in the keyhole. This symptom indicates that your ignition switch is badly damaged and needs to be repaired or fixed quickly.

This is a common issue with a key whose blades are more of a cylindrical design. The groves and notches gradually rounded and smoothed out over time. This stops the key from rotating the different pins in the barrel according to the correct positions.

4) Car starts and then suddenly stalls

If your car starts and then unexpectedly stalls, it is a clear symptom of a bad ignition switch. When the ignition switch is in the start position, it immediately takes power from the vehicle battery and turns on the ignition system and fuel pump. This allows your car to be started.

However, if your switch fails in the “on” position, it will not deliver power to the fuel pump and ignition system as soon as you pull the key from the start position to the “on” position.

5) Issues powering on the accessories

A faulty ignition switch doesn’t properly supply power to the electrical accessories of your vehicle. Inserting the key and turning it to the “acc” position activates the ignition switch and turns on the vehicle’s electrical parts, like the center console, dashboard, and interior lights.

If your vehicle’s accessories don’t get power as you insert and turn the key, it means that your ignition switch is faulty. Similar symptoms can also be produced by fuse or wiring issues. Therefore, in such a condition, you should properly diagnose the issue.

6) Ignition is constantly turned On

There may be an issue with your ignition switch if you shut off your car, but surprisingly the car keeps running even with the ignition off and the key removed.

It’s not very common, but it happens. Once the immobilizer is unlocked, the key does not need to be detected again until it is reset, allowing you to drive without a key.

7) Silent Starter Motor

A quiet starter is one of the major symptoms of a faulty ignition switch. In such a case, put the transmission in neutral and recheck to see if the neutral safety switch is the problem. If you hear any clicking sound from the motor, there may be something other than an ignition switch problem.

8) Stuck steering wheel

The ignition lock has a mechanical lock for the steering wheel. This lock protects your vehicle by stopping the steering wheel when parking. If your vehicle has an issue with the steering lock, it means that the ignition cylinder needs to be checked for service.

Causes of a Bad Ignition Switch

1) Broken-off Key is Stuck Inside the Ignition Switch

The broken key in the ignition lock is one of the major causes of a bad ignition switch. Your key wears out with time, weakening and ultimately breaking into the ignition switch.

2) Bad Wafers

A wafer is a unique set of cuts in each ignition lock that allows you to identify the unique key for that car. Your vehicle’s wafers may clog up with dirt and grime from daily wear and tear. If they are worn out and no longer respond to key insertion, the key cleaning can repair individually worn wafers or replace the complete switch.

3) Transponder doesn’t Communicate with PCM

If your vehicle has problems with the security system or the key fault light on your dashboard indicates an issue, there is a high chance that your PCM chip is faulty or it needs reprogramming. In such a case, you will need to reprogram or copy the original key to create a new key.

4) Manufacturer Fault

In some cases, a faulty ignition switch can cause an entire problem. If your vehicle is still under warranty, most vehicle manufacturers will replace it for free if it is defective.

5) Faulty Key

Your vehicle key wears out with the passage of time. In such conditions, unique grooves on each key become worn, which may cause the ignition to not respond. Try a spare key to make sure it is the key and not a faulty ignition switch. If everything is ok, you need to change the key.

How to start a car with a bad ignition switch?

Follow one of the below-given methods to start your car with a bad ignition switch:

1) Hotwiring

If your vehicle is manufactured before the mid-1990s, this method is best to start a vehicle with a bad ignition switch.

  • First of all, locate the steering column.
  • Remove the plastic cover that holds all the inner components in place. This will show you all the parts you will need.
  • Now find the wiring harness connector. There are many cables and wires in this area, so finding a specific connector can be difficult. But mostly, it’s in the middle of the steering column. Other connectors, cables, and wires are connected to the light control wipers and other parts.
  • Next, you need to find the connections for the starter motor, ignition, and battery.
  • The brown and yellow wires refer to the ignition switch. The red wire refers to the battery.
  • Strip the battery cables 1 inch below the insulation and twist them together.
  • Connect the ignition switch wires to the battery wires, and your vehicle’s lights will come on, and the electrical components will start working.
  • To start the engine, strip the starter motor cable 0.5 inch and connect it with the linked battery cable.
  • The engine should now start. So, let’s start the engine for a while.

2) The drill and screwdriver

This method can also work but be careful as it may completely damage your ignition switch. Follow the below-given steps to start your car with a faulty ignition switch.

  • Find the keyhole
  • Use a metal drill to drill out the keyhole according to the length of the key. This process can damage the ignition cylinder’s inner pin.
  • Take a screwdriver, insert it in the keyhole like the key, and turn on the ignition. In this way, your car will start.

3) Jumper Cables

  • First of all, open the hood
  • Locate the battery and ignition coil.
  • Use a jumper cable to link the positive side of the battery to the coil’s positive side. This will supply power to the circuit board, which is required to start the engine.
  • Find the starter solenoid and connect the solenoid to the battery-positive terminal. Next, disconnect the ignition switch harness from the solenoid.
  • Use a screwdriver to short the positive pole of the solenoid to the terminal where the ignition switch is mounted.
  • This activates the solenoid and starts the car.

What wires go to the ignition switch?

Most cars have four wires that go to the ignition switch for the ignition input, start, battery, and accessory. As such, you’ll find that your ignition switch generally has four terminals with wire connections.

If your ignition switch fails, an auto repair shop might charge you a pretty penny to diagnose and fix the issue. However, you could also make it a DIY project to save money.

These switches typically have four terminals with the labels:

  • IGN (ignition input): This is the primary terminal that controls your car’s ignition and other electronics. It may be connected with a yellow or red
  • BATT (battery): thick red wire that is always energized usually connects here.
  • ACC (accessory): This terminal delivers power to the parts on your vehicles, such as the windshield wipers, radio, and lights. This terminal usually contains a purple
  • ST (starter): This terminal links to the starter solenoid. It may have a yellow or brown

Ignition Switch Replacement Cost 

The replacement cost of the ignition switch varies according to the vehicle model, labor cost, and the type of brand. The average replacement cost of the ignition switch is from $110 to $260. An ignition switch costs from $30 to $70, while labor costs $80 to $190.

Ignition Switch Location

The ignition switch of your car is typically located on the back of the ignition lock cylinder where you insert the key.

To locate the ignition switch:

  • Remove all the covers around the steering wheel
  • Disassemble the whole ignition lock cylinder
  • In a few cars, you can remove the ignition switch from the ignition barrel – but sometimes, it is an integrated part.

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