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.
Knowing The History Of Neutral Safety Switch
Now that you know ‘what is a neutral safety switch,’ let’s get an idea about its history.
The era around 1960 was the time where the automotive industry took some noticeable turns for ensuring safety in vehicles. As the year went by, many safety gears came to light such as seat belts and neutral safety switch.
The switch very first took place in 1950 and by 1980 it was a common tool in every automobile.
Normally, the neutral safety switch can be found inside the transmission case or anywhere near the gears system.
It was introduced to prevent accidents from taking place in case you leave the kids alone in the car. To the surprise, the tool is working commonly in almost all the cars these days ensuring the protection.
What Is a 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.
The Function of a Neutral Safety Switch
Your vehicle’s neutral safety switch is there to ensure that you can only start your vehicle with the transmission in neutral or park.
This is a critical function because if you try to start your vehicle while the transmission is in gear, you can cause engine damage, and if you’re not careful, your engine can launch.
Another feature of the neutral safety switch is that it prevents you from accidentally engaging your starter when the engine is running.
If this were to happen, you’d likely damage your starter and engine, and it can lead to an accident. Not only can this be extremely expensive, but it can be dangerous too.
There is a reason safety is in the name of the switch, the neutral safety switch is a critical safety function that keeps you from damaging your engine or accidentally hurting someone.
However, when this component malfunctions, it can prevent you from starting your vehicle in any gear, or it can allow you to start your vehicle in any gear at any time. Either condition can lead to big headaches.
How to Locate the Neutral Safety Switch in Your Vehicle?
The exact location of the neutral safety switch can vary from vehicle to vehicle. On newer vehicles with an automatic transmission.
It is typically within the transmission housing where it is mounted to the side or directly connected to the shift linkage. You should look for small and rectangular box-like component.
For those with older vehicles, the switch might be directly integrated within the steering column near the shifter itself. Front-wheel drive vehicles, on the other hand, will often have the NSS attached to the transmission case, which is accessible from under the hood.
If you aren’t sure where your neutral safety switch is, simply check your vehicle’s repair manual, which includes diagrams of the car, or look it up online through your car’s manufacturer.
Bad Neutral Safety Switch Symptoms
The signs of a failing neutral safety switch can easily be mistaken for other faults in the engine, electrical system, or transmission.
Often, you have to take all the various symptoms into account and perhaps take a few minutes to rule out other faults before assuming the issues you’re seeing are indeed a failing neutral safety switch.
#1. The Engine Won’t Crank.
The engine not even attempting to crank is one of the most common signs of a neutral safety switch problem. From the switch’s perspective, it thinks you have the car in drive or reverse, and it’s doing its job of preventing the engine from starting.
However, this could easily be mistaken for a battery problem or a completely burned-out starter. If you hear a “Click” and the lights are dim when you turn the key into the ON position, then it’s likely the battery, and you should test it with a multimeter or voltmeter.
If it’s the starter, you likely would have noticed starting problems in the past. Not the least of which are ugly metallic grinding noises when you try to crank the engine.
If you haven’t noticed either of these signs, then it’s a strong indicator that the neutral safety switch is going out.
#2. The Car Hesitates to Shift Gears.
The neutral safety switch is typically integrated with the transmission, which can cause the car to hesitate when shifting gears. Especially when starting out in first gear or shifting the car from neutral into reverse.
This can mimic various transmission problems, such as low transmission fluid or a problem with the TCM or a shift solenoid.
If you check the transmission fluid when the engine and transmission are cold, and it’s normal for the COLD mark, and it looks normal, you can rule out the fluid.
If the TCM fails or you have a bad shift solenoid, you’d likely get the check transmission or check engine light flashing when shifting into first gear or reverse. This would then throw a code that would be specific to the transmission’s performance.
- CodeP0750 indicates a shift solenoid problem.
- Code P0613 is a general code for a connection problem with the Transmission Control Module.
- Codes P0700 and P0706 indicate shifting problems caused by a TCM issue.
#3. The Car Stalls Shortly After Going Into First Gear.
The car starting but then shifting hard and finally stalling just as it gets underway in first gear is another possible sign of a bad neutral safety switch.
Here again, the switch is misreading whether the car is actually in gear or neutral, and it’s engineered with a bias toward safety, which is letting the transmission fall back into neutral.
A lot of times, once it stalls, the car will refuse to restart again. You might have to wait or even go so far as to disconnect the battery for 5 minutes before it will even attempt to let you try to start it again.
Here again, this could also be misinterpreted as a low transmission fluid problem, a failing TCM, or a problem with the torque converter.
If it is the torque converter, you will likely feel shuddering at all gear shifts, especially when downshifting or accelerating hard. It likely would have shown you signs of a major transmission fault long before this point, further indicating a neutral safety switch problem.
#4. The Car Will Start in Neutral but Not in Park or Vice Versa.
One of the odd quirks you find in a lot of failing neutral safety switches is that the car will start in neutral, but it won’t crank at all if you have the transmission in park.
Of course, the reverse is also possible. A failing neutral safety switch might allow the car to start in park but not in neutral.
If you always start your car in park, this might head-fake you into thinking that it’s actually a bad ignition switch or some other electrical gremlin.
So, it’s always wise to put in the due diligence to try both. If the engine cranks and starts normally in one but not the other, it’s another strong vote for a neutral safety switch problem.
#5. The Backup Lights Won’t Come On.
Another odd symptom of a bad neutral safety switch is your backup lights not coming on when you put the car in reverse.
You might not realize it until you start backing slowly out of a parking spot, only to have someone honk at you, unaware until the last second that you were backing toward them.
This is the bad neutral safety switch failing to recognize the gear you’re in and often thinking that you’re in the Park when you quickly shift it into reverse.
#6. The Check Engine Light Comes On.
A failing neutral safety switch can cause the check engine light to come on. When it does, the car’s computer throws a code you can check on an OBD II scan reader.
Code P084F indicates a malfunctioning neutral safety switch. If you don’t have a code reader, most auto parts stores will hook it up to their reader for free.
What Causes Neutral Safety Switch Failures?
#1. Internal Wear and Aging.
The neutral safety switch, as with many mechanical and electrical components, is subject to wear and tear over time. Prolonged use can cause the switch’s internal contacts to degrade, leading to inconsistent or complete failure in transmitting electrical signals.
#2. Exposure to Contaminants.
Contaminants such as dirt, moisture, or transmission fluid can seep into the neutral safety switch, especially if its seals are compromised. These contaminants may corrode or obstruct the internal components of the switch, disrupting its functionality.
#3. Electrical Circuit Failures.
Faulty wiring, loose connections, or damaged terminals in the neutral safety switch circuit can prevent the proper flow of electrical current. These issues may arise due to excessive vibration, physical damage, or improper installation.
How do you test a neutral safety switch?
When the safety switch fails, it requires several form of tests to see whether you need to do a neutral safety switch replacement or adjustment.
#1. Check with a Manual Transmission.
In addition to checking the effects of the neutral safety switch in different gear positions by exclusion as above, you can execute the test in another way for your manual transmission.
Method 1: Check the wiring.
- Locate the safety switch. This type of switch is usually located near the end of the clutch pedal lever or on the push rod that connects the pedal to the master brake cylinder.
- Disconnect the electrical connector from the switch.
- If the connector has two wires, use a jumper wire to connect the terminals. If there is only one wire, connect the terminal to a good ground with a jumper wire.
- Put the transmission in N.
- Try to start the engine. If the engine starts, the switch may need to be adjusted or replaced. If it doesn’t, the problem is most likely in the starter circuit.
Method 2: Multimeter test.
- Set the digital multimeter (DMM) to the lowest resistance or continuity test mode.
- Disconnect the switch electrical connector.
- With the clutch pedal released, touch the multimeter leads to the switch terminals. The meter should show no continuity (no beeps or “OL” reading).
- If there is continuity, replace the switch.
- Then, depress the clutch pedal and repeat the test. The meter should show continuity. If not, the answer is to replace the switch.
- Again, if it is adjustable, try adjusting it according to the repair manual and retest.
#2. Check with an Automatic Transmission.
Before attempting to adjust the switch, you can perform a few preliminary tests to determine the condition of the switch on the automatic transmission.
Although not a formal test, this test can lay the foundation for further steps, such as adjusting or replacing the switch.
Quite similar but more complex compared to the manual-transmission-based test above, this test includes these following.
Functional check
- Press and hold the brake pedal throughout the test.
- Try starting in Park. Turn the key to the “start” position for 2-3 seconds. Check if the engine cranks.
- Move the gear shift to neutral. Turn the key to the “start” position for a moment. Check if the engine cranks.
- Try starting in Reverse and Drive (one gear at a time, for a moment). The engine should not turn in any gear other than Park or Neutral. If it does, the switch is faulty.
Wiggle Test
- Turn the key on, turn the engine off: Turn the key to the “on” position (do not turn the engine).
- Gently rock the gear shift back and forth between Park and Neutral without actually shifting gears.
- Observe while starting. If the starter engages or the engine attempts to start, the switch neutral safety or wiring may be faulty.
#3. Check the light or multimeter (Wiring diagram required).
Locate the switch and connector. Refer to the repair manual if unsure. Use the wiring diagram to locate the wires involved in the starter circuit at the neutral safety switch connector.
Disconnect the electrical connector from the switch and perform one or two procedure below.
A test light
- Connect the test light clamp to a good ground.
- With the key in the “on” position, check the appropriate wires on the switch connector while the transmission is in Park. The test light should illuminate.
- Test with the transmission in Neutral. The test light should illuminate.
- Test with the transmission in Reverse and Forward. The test light should not illuminate.
Use a multimeter
- Set the multimeter to the continuity test mode (or lowest ohm range).
- Connect the multimeter leads to the appropriate terminals on the switch connector while the transmission is in Park. The meter should show continuity (beeps or near zero resistance).
- Test in Neutral, Reverse, and Drive. The meter should show continuity in Neutral and no continuity (no beeps or “OL” reading) in Reverse and Drive.
After testing the above with the safety switch, we can rely on the following results to summarize its condition.
- The neutral safety switch may be faulty and needs to be replaced if these signs show:
- The engine only cranks in Neutral
- The engine turns in any gear other than Park or Neutral
- The engine cranks in any gear other than Park or Neutral
- Test light/Multimeter shows incorrect continuity
- Engine turns during wiggle test: Switch or switch wiring may be faulty.
When the engine does not crank and continuity is correct, the problems could be the starter motor, wiring, solenoid, etc. Then, you need further investigation.
How to Replace a Faulty Neutral Safety Switch?
Step 1: Locate the Neutral Safety Switch.
- The neutral safety switch is typically mounted on the side of the transmission, near the shift linkage.
- In some vehicles, it may be part of the transmission range sensor (TRS).
- Refer to your owner’s manual or repair guide for the exact location.
Step 2: Lift the Vehicle (If Necessary).
- If the switch is hard to reach, use a jack and jack stands to raise the vehicle and secure it properly.
Step 3: Unplug the Wiring Harness.
- Locate the wiring connector attached to the switch.
- Press the release tab and carefully unplug the connector.
- Inspect the wiring for corrosion, frayed wires, or loose connections. Clean the terminals with electrical contact cleaner if necessary.
Step 4: Compare the New and Old Switch.
- Before removing, compare the new switch with the old one to ensure they match in shape, size, and electrical connections.
Step 5: Remove the Old Neutral Safety Switch.
- The switch is usually held in place with two or three bolts.
- Use a socket and ratchet to remove the bolts.
- If the switch is stuck, gently pry it loose with a flathead screwdriver.
Step 6: Install the New Neutral Safety Switch.
- Align the new switch with the shift linkage and mounting holes (note fine adjustment may be required).
- Hand-tighten the bolts, then use a torque wrench to tighten them to the manufacturer’s specifications.
- Do not overtighten, as this could damage the switch or cause misalignment.
Step 7: Reconnect the Wiring Harness.
- Plug the electrical connector into the new switch.
- Ensure it clicks securely into place.
Step 8: Test the Repair.
- Turn the ignition to the ON position and shift through all gears to ensure smooth movement.
- Try starting the car in Park and Neutral to confirm the new switch is working properly.
- Attempt to start the car in Drive or Reverse—the engine should not crank in these positions.
Step 9: Clear Any Trouble Codes (If Applicable).
If the Check Engine Light was triggered by the faulty switch, use an OBD2 scanner to clear any stored transmission-related codes.
How To Do Neutral Safety Switch Adjustment?
Generally, if you are not a professional mechanic, there are two basic and most accessible methods to adjust the neutral safety switch. That is by sliding the switch or aligning the marks.
If you are unsure, even with the most basic step, you should consult your vehicle repair manual.
Method 1: Sliding the switch.
This method is less accurate and is generally not recommended in many cases.
You can use it as a reference, but it is best to follow the manufacturer’s recommended procedure.
- Loosen the switch mounting bolts enough to allow for horizontal movement. Use an appropriately sized wrench and socket.
- Have a partner quickly turn the ignition key to the “Start” position. They should release the key as soon as the engine starts.
- While the engine is starting, slide the switch to Park or Neutral until the starter cranks. Hold the switch in that position and tighten the mounting bolts.
- Verify that the starter motor starts in Park and Neutral, but not in other gears.
- Reassemble any removed parts, such as the control panel or screws.
Method 2: Aligning marks.
Compared to the first method, this method seems to provide a more precise adjustment.
- Loosen the switch mounting bolt/screw.
- Place the shift lever in neutral.
- Locate the neutral mark/line on the switch and align it with the corresponding mark/notch on the transmission or switch mounting point.
- Tighten the switch bracket just enough to hold it in the aligned position.
- Start the engine in neutral and park the vehicle. The engine will start in these positions but not in other positions.
- If the switch functions properly, tighten the mounting bolt/screw to the torque specification in the repair manual.
- In case the engine does not start or starts in the wrong gear, readjust the switch.
Neutral Safety Switch Replacement Cost
The exact cost of neutral safety switch replacement often varies significantly from one model of vehicle to the next. This is due to the wide range in parts costs, as well as the relative time required to replace the sensor itself.
However, as a general average, neutral safety switch replacement typically costs between $170-$250. In some extreme cases, the cost for such repairs can actually exceed $300, though this is quite rare.
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 the 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.
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 replace 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 a 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 gear 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.