car ignition

How to Bypass Ignition Switch to Start Car

If you cannot start your car and suspect the problem is because of a faulty ignition switch, or if you have lost your key, then if you own an older car, you may be able to bypass the ignition switch and start your car temporarily. Let’s find out how this can be done.

The only cars that can be started by bypassing the car’s ignition switch are those that work with an older ignition system built before about 2004. Cars that use an ignition key to start, work by turning a mechanical switch, normally on the steering wheel column, and this, in many cases, can be bypassed and the car started.

More modern cars have keyless ignition, meaning you can turn them on without inserting a key. This was a security feature introduced to make stealing cars harder. These cars cannot have their ignition bypassed in the same way.

If your car doesn’t have this feature, or if it was built before 2004, bypassing the ignition switch may be a way to start your car in an emergency.

Why Would You Want to Bypass An Ignition Switch to Start The Car?

There are a few possible situations in which you might want to start a car and cannot use the key to start it. Some of these are:

  • The ignition switch is stuck or locked and you can’t turn the key to start your car.
  • The ignition switch is broken and your can’t won’t start.
  • You have lost the key to your car and can’t get hold of another one.
  • You have a car without its ignition key and want to start it.

The other reason, which we don’t want to condone here, but is a reality, is that bypassing an ignition switch enables a car to be stolen easily. I hope you are not checking this in order to steal someone’s car!

Bear in mind that most older cars, (except for very few rare models), use an ignition key, so what we are about to discuss does not apply to newer cars.

In days gone by, and as seen in many movies, thieves often broke into cars by “hotwiring them”. The process of hotwiring a car and details of which cars this can be done on has been covered on this page if you want more information on this.

Also, some owners of older cars like the idea of installing a push button to start their car easily, this continues to be a popular thing to do though it is less secure and makes it very easy for a thief to steal your car. if you know how this is quite an easy project for owners of older model cars.

How Does a Car Ignition Switch Work?

The traditional ignition switch has been used in cars for many years. It is basically a switch like any other and turns on the power from the car battery. The idea is that the key when turned in the ignition sends a surge of power from the ignition coil that is then sent to the spark plugs. This causes a spark that lights the fuel that has been injected into the cylinder. This fires up the engine and this is how the car starts.

The car ignition switch has three parts: the stationary inner contact, the movable outer contact, and a spring-loaded plunger. When you turn on your car’s ignition with the key, the stationary inner contact connects with the movable outer contact and completes an electrical circuit that starts your vehicle.

If the ignition switch fails for some reason no power is sent to the ignition coil and the spark plugs cannot light the fuel in the engine cylinder. The engine will turn but not fire.

One way to start the engine, logically, would be to bypass the ignition switch and connect the power directly to the ignition coil. In order to do this, we need to locate the ignition switch and identify the wires that carry the power to and from the switch to the coil. By bypassing the switch we can reconnect the circuit and start the engine.

This is the basic setup and function of any older car (by older we mean pre-2004 or even earlier for some models). After this date, safety measures were introduced to prevent cars from starting simply by bypassing the ignition switch and hotwiring the car. This was intended to reduce the large number of vehicles being stolen in this way.

The Difference Between Ignition Systems in Modern Cars and Older Cars

The first car to use an ignition switch and key was designed by Charles Kettering in 1897. The driver would turn the handle on the floorboard, which turned a starter motor that would start the engine.

Some vehicles still use an electrical ignition switch system today, but very few. Today, not all cars have an ignition switch.

In more modern cars changes were made which involved adding an extra part to the ignition circuit of the car to make it harder for someone to start the car without the key. In newer cars today, keys are not physically used to start the car, however, they must be present in the car for it to start. The idea is that without the key you cannot start the vehicle. This all works with a computerized chip-based system and unique code that the key sends to the car.

So, in short, modern cars can not be started merely by bypassing an ignition switch. The process to start these is more complicated but not impossible. As with all computerized systems, they can be hacked and the system can be tricked into believing that the key is present.

How Easy is it to Bypass the Ignition Switch and Start a Car?

So, assuming you want to start an older car with a mechanical ignition system and key, how difficult is it?

The process for bypassing the ignition switch on your car will vary depending on what type of model you have.

However, generally, it is not as easy as is shown in the movies ie. ripping out a couple of wires and twisting them together then off you go! But, depending on the model and year of the car you have it will be easier or more difficult. We will look at a few examples here.

One solution for bypassing the ignition is proposed by one reader on the Motor’s Forum:

This solution involves connecting two wires. The first wire connects the 12V from the battery of the car to a push-button switch and then a second wire runs between the switch and the starter solenoid. In order for this to work, the key must be in the ignition and moved to the start position. The need for the physical key to be turned into this position adds a little more security. When the push button switch is pressed, the car will start thereby bypassing the ignition.

How to Identify Wires in Ignition Switch

In many older cars in the steering column, you can remove the plastic cover to reveal the ignition switch. For example, in a Honda Accord, the ignition switch sits in a plastic holder underneath the steering wheel. Here’s how to identify the different wires and understand how to get the ignition to start:

  1. Pull out the ignition switch from the plastic holder. You should see five wires.
  2. To identify which wire is the one which connects directly to the battery positive terminal use a voltmeter and touch it to the wires. The negative voltmeter probe should be clamped or touching a grounding point. Be careful not to short anything out and do not touch any of the wires yourself. If you touch a wire and it reads 12V with the ignition switch in the off position, then this is the permanently connected positive wire which goes to the positive terminal of the battery.
  3. Next, verify that the other wires are at 0V. There shouldn’t be any voltage here with the ignition switch in the off position.
  4. Now, turn the ignition key into the on position and test the wires again. Go to the wires that were 0V in the previous step and what you are looking for is one of these wires to now be at 12V, when you find it this is the starter wire.
  5. Now to hotwire the car you need to connect the battery terminal wire which is always at 12V to the two ignition wires (ignore the starter wire and the earth wire). How to connect them? Best way is to remove the insulation on the wires in a certain place and use another wire to wrap around the bare wires to complete a circuit. The car will start and run as long as a continuous connection is made. For exactly how this is done on a Honda Accord, check this explanatory video. Note that this video also shows an example of how you can fit a push button starting button, if that’s something you’d like to do.

Which Cars Can Be Started By Bypassing the Ignition Switch?

Basically, most cars that were produced before 2002 can be “hotwired” by bypassing the ignition and some models up to 2004.

Some common examples of cars that use an ignition switch and key:

  • Audi, BMW, Buick, Chevrolet, Dodge, Ford Fusion Hybrid 2007-2010 (2007-2012 in Canada),
  • Jaguar XJ8/XJ6 2005-2009 models (2005-2012 in Canada)
  • Jeep Patriot 2007-2010 (2007-2012 in Canada)
  • Lexus RX350 2010 model year (2010 to 2012 in Canada)
  • Mercedes Benz C250 2008 model year (2008 to 2012 in Canada)
  • Honda Accord (especially until about 1998). This model is reputed to be one of the easiest cars to hotwire and thieves loved it. After about 1998 security features started to be introduced which slowly reduced theft of these cars.

Conclusion

Now that you are aware of how to bypass the ignition switch of an older model car, you should be able to appreciate how much safer the modern car is. Keyfobs which have a chip inside, special codes that are sent to the engine and without which you cannot start the car are offputting to thieves, but unfortunately not impossible to overcome.

Despite this added safety, if you do get stuck in your car and cannot start the ignition for some reason you will probably require some assistance if anything goes wrong with the ignition system or keyfob. Therefore, be sure to take care of your car’s keyfob and always be sure to keep it in a safe place.

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