Neutral safety switches prevent you from starting your car in any gear other than neutral or park.
In an automatic transmission vehicle, the neutral safety switch only allows current to pass to the starter motor when the gear lever is set to either the neutral or park position. The neutral safety switch is typically connected to the shifting linkage and located on the side of the transmission.
In a manual transmission vehicle, the neutral safety switch is also called the clutch safety switch. It has the same purpose, but it requires the driver to press down on the clutch before the switch allows current to pass to the starter motor.
The switch is an important safety component that eliminates the risk of an accident at the time of starting a car.
How Does A Neutral Safety Switch Work?
When you turn your key to start your engine (or push a button), the battery sends a current to your engine’s starter. This tells the starter to fire up your engine so you can get on the road. The neutral safety switch simply disrupts that current if your car is in any gear other than neutral or park.
This is only true for vehicles with an automatic transmission. Manual transmissions have a similar apparatus attached to the clutch pedal. The clutch neutral switch prevents a vehicle from starting unless the clutch pedal is pressed. This is a simpler design than the neutral safety switch for automatics, and it’s cheaper to replace.
Where Is The Neutral Safety Switch Located?
On an automatic transmission, the switch is often mounted to the side of the transmission itself, connected to the shifting linkage. It can also be located on the steering column on older vehicles with column shifter.
Some modern electronic transmissions without a traditional shifter linkage (shift by wire) use a transmission position sensor (either internal or external) which also serves as a neutral safety switch.
The switch is connected in such a way that any transmission shifter location that places it in gear will interrupt the starting sequence. This is what tells it when the proper conditions are met to send current.
On manual transmissions, there’s a switch with a similar function on the clutch linkage typically near the clutch pedal itself called the clutch safety switch. Depressing the clutch pedal allows for the vehicle to start because if the clutch is pushed in, the transmission is now disconnected from the engine.
Symptoms of a Bad Neutral Safety Switch
A bad neutral safety switch can cause the vehicle’s starter motor to crank the engine while the transmission is in gear rather than in park or neutral. In that case, the engine will typically start and the vehicle will begin to move unexpectedly. Here are some symptoms:
#1. The Engine Doesn’t Start In Park But Starts In Neutral Mode.
When the driver turns the ignition switch and the automatic transmission is in park, or the manual transmission is in neutral and the clutch pedal is engaged, the car should trigger the starter to engage.
However, if they turn the key under these circumstances and the vehicle does not crank over, it may be caused by a faulty neutral safety switch inside the transmission or clutch pedal. Since this symptom may also be attributed to battery issues, broken starters, or other component failures, a certified mechanic will need to inspect this in person to determine the correct course of action.
#2. The Engine Doesn’t Start In Neutral But Starts In Park Mode
On the opposite side of the spectrum, when the vehicle cranks over when the transmission in in park but not neutral, it’s typically due to a faulty neutral safety switch. In this case, the switch is either experiencing an internal component failure where it is activating in one gear but not the other.
It may also be due to an electrical failure or that the switch is loose and needs to be adjusted. A certified mechanic can repair this issue if found early enough.
#3. The Engine Starts on Any Gear.
If your vehicle is experiencing this symptom, then the neutral safety switch isn’t functioning anymore. This could be caused by a shorted neutral safety switch. This is a safety hazard since the vehicle may start in gear and move, which may cause an accident. You should replace the neutral safety switch as soon as possible.
#4. The Engine Does Not Start At All
One of the common signs of a bad neutral safety switch is that the vehicle won’t start when the transmission is in park or neutral. No matter if your vehicle is in any gear or not, if the engine doesn’t start at all, then a neutral safety switch might be experiencing some electrical malfunction. In this case, there will be no power flowing from the switch to the starter relay.
This sign indicates an open electrical circuit in the safety switch which might be due to a blown fuse, broken relay or even an electric issue with the switch itself. The solution to this can only be the replacement of the bad neutral safety switch. You can find out the causes of car fuse damage here.
How Do You Fix A Neutral Safety Switch?
Because of the neutral safety switch’s location, it’s not always an easy part to replace. Most people simply opt to take their vehicle to a mechanic. In general, this is a good policy with problems that are electrical in nature. But there are some problem-solving steps anyone can do.
A bad car battery will exhibit many of the same symptoms as a bad neutral safety switch. Making sure you’ve correctly identified the problem is the first step to fixing it.
Apply your brakes and turn the ignition to start. Then move the shift selector through the different positions to see if the car is able to crank in any of them. If it works differently than expected, it’s most likely a neutral safety switch problem.
Another trick, or something you can do if your engine refuses to crank, is to try wiggling your shifter. If the neutral safety switch is misadjusted then it may need a little push to get into the right position.
Once you’ve determined that it’s the neutral safety switch, you can use your car’s manual to locate and replace it with a new neutral safety switch. Just remember to unplug the battery first! If you’re hesitant about doing your own electrical work, you can also take your vehicle to a trusted mechanic.
FAQs.
What happens when a neutral safety switch goes out?
The switch prevents the engine from starting when not in park or neutral. This eliminates the risk of starting an automatic car in drive or reverse mode. Located in the linkage or the transmission box, a bad neutral safety switch can cause irreversible damage to your car’s engine and transmission.
What does the neutral safety switch do?
Put simply, the neutral safety switch prevents the car from being started in any gear but neutral or park. Generally, this is a good thing…if you accidentally leave the car in gear, you won’t be able to start the car, which would unexpectedly start moving if it were in gear.
Do I need to replace neutral safety switch?
A faulty neutral safety switch may allow the engine to crank over and even start when the transmission is in gear. Such occurrences could result in serious personal injury or death. Therefore, it is highly recommended that you replace a faulty neutral safety switch immediately.
Is it expensive to replace a neutral safety switch?
Symptoms of a bad neutral safety switch include an engine that cranks in neutral or park but not both, an engine that refuses to start, and an engine that starts on any gear. Replacing a neutral safety switch costs between $30 and $550, and labor costs can cost an additional $78.