Know Bad Neutral Safety Switch Symptoms and Fix The Problems

A neutral safety switch is a safety mechanism featured in automatic cars. It is an essential electrical system component. This safety device allows the engine to start only in neutral or park. In addition, it prevents the engine from starting in gear.

If the neutral safety switch malfunctions, it’ll cause several issues. A bad neutral safety switch can lead to a collision, causing injuries and loss of lives. Therefore, it is important to know the symptoms of a bad or failing neutral safety switch and fix or replace them before something happens.

In this article, we’ll look at bad neutral safety switch symptoms, how to test a neutral safety switch, and how to fix it. But first, let’s see what it means.

how to test a neutral safety switch

What Is Neutral Safety Switch

A neutral safety switch is a safety mechanism that prevents an automatic gear from starting when in gear. Auto manufacturers mount this component on the transmission, enabling the vehicle to start only when the vehicle is in neutral or park.

It works in harmony with the starter motor. When the driver switches the ignition key to the ‘ON’ position, the neutral safety switch allows the electric flow to travel to the starter solenoid and the ignition system. This engages the starter motor and helps start the ignition process by turning the flywheel.

The manufacturers designed it to prevent potential damage to the transmission and starter motor. But, most importantly, it is designed to reduce collisions.

However, the vehicle should be in the park or neutral to allow electric flow to the starter solenoid. If the safety switch is bad, it can cause a car won’t start after several attempts. It can also cause hard gear shifting and engine hesitation, and stalling. So, if you were asking, can a bad safety neutral switch cause shifting problems? You now know the answer.

Bad Neutral Safety Switch Symptoms

Several vehicle components fail over a period and need repair or replacement. However, these components project some symptoms to notify the driver of an underlying system problem.

Here are some common signs of a faulty neutral safety switch that shows an imminent issue.

Bad Neutral Safety Switch Symptoms

Check engine light

The vehicle powertrain control module (PCM) triggers the check engine light whenever there’s a problem in the electrical or mechanical systems. Several malfunctioning components can trigger this engine warning light. So, when it comes up, you need to run a system diagnosis to track why the light illuminates on the dashboard.

Since the neutral safety switch is an electrical system component, it’ll cause the engine control module to trigger the check light whenever it malfunctions.

The vehicle won’t start in park but starts in neutral

Automatic vehicles should start in park and neutral. They have a unique design that enables them to start only on park or neutral. 

When you get inside the vehicle and try starting the vehicle in park, and it doesn’t start but starts in neutral, you have a faulty neutral safety switch on the vehicle.

It’s important to know that this can signify a faulty starter motor, battery issues, or other system component problems. Therefore, you need a thorough diagnosis of the probable causes before concluding a defective neutral safety switch is the culprit.

The vehicle won’t start in neutral but starts in park

On the other hand, if the vehicle starts in neutral but won’t start in park, it shows you have a malfunctioning or damaged neutral safety switch. So in situations like this, the safety mechanism is working partially.

It has an electrical failure, or it is loose and needs to be adjusted. This is a sign of an early failure. An experienced mechanic may repair these issues at this stage without replacement. If you ignore it for an extended period, it’ll drop expensive repair bills on the table.

The car won’t start at all

Several issues within different vehicle systems can prevent an engine from starting. One of them is a faulty neutral safety switch. When a neutral safety switch experiences some electrical malfunctions, it can prevent the engine from cranking.

This could mean you have a blown fuse or relay on the corresponding neutral safety switch wire. The switch could also be the culprit. The only fix is to replace the blown fuses or relay, fix the wiring issues, or replace the neutral safety switch.

The vehicle starts in any gear

As explained above, auto manufacturers design automatic cars to start only in neutral or park. Therefore, the neutral safety switch is bad if the car starts in any gear. It could also mean you have wiring issues, such as short or open circuits on the wiring harness.

If your automatic car starts in any gear, you’re in serious safety issues. It is as bad as driving without any neutral safety switch installed in a car. You won’t want to ignore this problem and continue driving with the vehicle. So, fix or replace it as soon as possible to avoid the repercussions.

It is important to note that these are just the signs of a bad neutral safety switch. It doesn’t necessarily mean you have a faulty neutral safety switch. Therefore, whenever you notice these symptoms, you need to test the switch or perform a bypass check on the switch. So, you’ll learn how to bypass the neutral safety switch in subsequent sections.

How do you test a neutral safety switch?

Before considering a neutral safety switch replacement, you need to ensure it is bad. Here are the methods to check the switch.

Method 1: Locate the Switch and examine the wiring harness

Neutral safety switch locations vary from vehicle to vehicle. So, the first step is to figure out its location in your vehicle model. You can consult your vehicle service or owner’s manual. It is your manufacturer in print.

However, it is located on the gear lever mechanism on most vehicles. It is threaded on the side of the transmission on column switch cars.

Inspect the electrical harness and connectors once you locate the neutral safety switch. It is wired to the solenoid. When the vehicle is engaged in any gear, the switch stays open and prevents electric flow to the starter solenoid.

The moment you turn the ignition key to the ‘ON’ position, the switch will transmit current to the starter to enable it to crank the engine. However, the vehicle must be in neutral or park before it grants electric passage to the starter. Therefore, any wiring issues will disrupt the optimal operation. So, you need to check the switch and ensure everything works perfectly fine.

Method 2: Check if there’s power in the neutral safety switch

Insert the key into the ignition and switch it to the ‘ON’ position. Do not start the car yet. Check if there’s any electric current on the wiring harness. You’ll need a 12v test light to conduct this test.

If the test light illuminates, there’s power in the wiring harness, and the switch is working pretty fine. Once you confirm the switch is okay, connect the wiring harness back to the switch. However, if the test light did not light up, inspect the wires for frayed or burnt areas or loose connections.

If the wires are good and there’s no power yet, you may have to install a new switch. Also, you could have a burnt fuse in the corresponding line. So, if you’re asking, is there a fuse for the neutral safety switch? You’re better informed. It has a fuse for protective purposes.

Method 3: Try starting the vehicle in different gears

You can also figure out if the safety switch is bad by trying to start the vehicle in a different gear range. Now, is this practice safe? You’ll be absolutely fine by following the procedures below.

  • Return the gear selector to park. Then, try starting the car.
  • If the vehicle doesn’t start in park, shift the selector to neutral. Then, depress the brake pedal and try starting the car.
  • The switch is bad if it starts in neutral but won’t start in the park.
  • Also, if it starts in the park but won’t start in neutral, the safety switch is malfunctioning and needs replacement.

Method 4: Test the neutral safety switch using a voltmeter

Put the vehicle in park and turn the ignition to the ‘ON’ position. Open the hood and locate the ‘fuse and relay’ box. Locate and unplug the starter relay. You’ll need a voltmeter for this test.

To proceed with this test, ground your voltmeter and test the volts with a relay port using the positive probe on the voltmeter. With the transmission in park or neutral and the ignition turned to the ‘ON’ position, it’ll provide power to the contact on the starter relay port.

You should have around 12 to 13 volts on the voltmeter. It’s important to note that you won’t see any voltage if the vehicle is not in park or neutral. Once again, the vehicle must be in the ‘ON’ position before conducting this test. Now, you can watch this video for visual clarification.

This method is more straightforward. In fact, it is my old school thing and I recommend you try this method. Get a voltmeter if you don’t have one.

How do you fix a neutral safety switch?

If the diagnosis proves you have a bad neutral safety switch, replace it immediately. Ignoring it for an extended period can be detrimental. If you’re a DIYer, you can fix the issues yourself if the switch is mounted on the side of the transmission.

However, if the switch is located on the shifter linkage or within the transmission housing, you may have to contact your mechanic. Your service manual will help you locate the switch.

Once you locate the switch, see if you can do the repair or need professional assistance. Another thing to consider is to have the right tools to access and replace it. If you have the right tools and the confidence to carry out the task yourself, proceed with it.

If the switch is bad, the only option is to replace it. First, remove the electrical connector on the switch. It’s much like a socket on the headlights. Unplug it and lose the mounting bolts. After that, wiggle it a bit to remove it. If it’s too stubborn, pry it off with a screwdriver.

Reconnect the wiring connectors and connect the battery. Test the switch by starting the vehicle. You have done a nice job if the vehicle starts in park and neutral but does not start in any other gear. Congrats. Reinstall every other thing you removed earlier.

FAQs:

Q: What problems can a bad neutral safety switch cause?

A bad neutral safety switch cannot prevent you from starting your vehicle in most cases. But it may pose several issues to the engine and transmission. First, a defective neutral safety switch will disrupt the smooth gear operation. In other words, it’ll cause gear shifting issues.

It may only cause engine stalling and hesitation, resulting in improper operation. However, it’ll prevent the engine from starting in a worst-case scenario.

Q: Can I bypass neutral safety switch?

Yes. You can bypass a neutral safety switch. Be warned, that if you don’t do this properly, you may fry your corresponding wiring harness. How to bypass the neutral safety switch is quite simple. However, it varies from vehicle to vehicle. Therefore, you may consider watching this video as a visual presentation that can offer better exposure.

Q: When should you replace a neutral safety switch?

The neutral safety switch is an essential safety component in vehicles. If it goes bad, it leaves the vehicle without the designated safety protection. If you ignore it and continue driving your vehicle, it may lead to a catastrophic road accident.

Therefore, always diagnose this switch whenever you notice any symptom that shows malfunctioning and replaces it. These symptoms include;

  • The car won’t start in park but starts in neutral
  • The car won’t start in neutral but starts in the park
  • The car starts in any gear
  • The car won’t start at all
  • Check engine light.

The last two can be starter or neutral safety switch issues. In contrast, the first three signs are most likely a sign of malfunctioning neutral safety switch issues.

Q: Is a transmission range sensor the same as a neutral safety switch?

The transmission range sensor is a safety device that detects the position of the gear selector and prevents the car from starting in any gears aside from park and neutral. It is also called a neutral safety switch. It is threaded on the transmission or gear shift linkage.

The sensor reads the gear position and signals the powertrain control module. The PCM then detects when to start the car and controls the gear shifting.

Final Words

Most people often overlook a bad neutral safety switch, thinking it’s a minor issue. However, the component plays an important safety role and prevents road accidents. If your vehicle projects bad neutral safety switch symptoms, diagnose and fix the culprit as soon as possible.

Don’t wait until a check engine light pops up on your dashboard. If you notice two or more symptoms outlined above, do what is needed. The test and replacement procedure is simple. You can do it yourself. However, if you don’t trust your guts, contact your mechanic to do the replacement.

Osuagwu Solomon

Osuagwu Solomon is a seasoned automotive technician for the past 9 years, and a technical writer. He loves writing about auto professional repair guides, DIY repair guides, and buyer’s guide. After spending six years in the automotive workshop, he decided to impact his knowledge to people aside his domain, and he has achieved this by centering his Automotive writing skills on REPAIRS.

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