How To Repair A Neutral Safety Switch

Dan Ferrell writes about practice-information technology-yourself car maintenance and repair. He has certifications in automation and command applied science.

Is There a Problem With Your Neutral Safe Switch?

Here are some signs that your vehicle may have a problem with the neutral safe switch.

• Your vehicle starts in a gear other than Park or Neutral.
• Your backup lights don't come on when in reverse.
• The gear option on the dashboard doesn't represent with the actual shift lever selection.
• The vehicle only starts in Neutral.
• Your vehicle does not outset at all.

In automatic transmissions, the neutral safety switch (also known as the starting safety switch) is a switch, normally open, that keeps the starting system from operating while the transmission is in gear. The vehicle should only start when the shift selector is in Park or Neutral.

On newer vehicles, this switch too turns the redundancy lights on and off and communicates with the car and torso computers nearly gear positioning.

In manual or standard transmissions, a clutch safety switch or starter/clutch interlock switch accomplishes its safety goal past requiring the driver to fully depress the clutch pedal to start the engine.

When the safety switch fails, you can do a series of tests and come across if it is just a matter of adjustment (if it is an adaptable blazon of switch) or if you really need to replace it. Depending on the detail set up or configuration of your switch, you lot tin can test information technology with a small-scale jumper wire, a examination light, or a digital multimeter (DMM).

Just jump to the appropriate section for your vehicle—automatic or manual transmission switches—and start checking your switch.

Alphabetize
1. Tools You'll Need
two. Checking a Neutral Switch on an Automatic Manual
3. Checking a Neutral Switch on a Standard Transmission
iv. What if my Switch Tests Okay?

On a manual transmission:

• Voltmeter
• Small jumper wire

On an automated transmission:

• Ratchet
• Socket fix
• Standard screwdriver
• Phillips screwdriver
• Flooring jack (if necessary)
• Two jack stands (if necessary)
• Two wooden blocks (if necessary)

Neutral rubber switch next to the selector stick.

Photo courtesy of Nick Ares on Flickr

two. Checking a Neutral Safety Switch on an Automatic Transmission

Before you try to suit the switch, you can do a couple of preliminary tests that tin can requite you a clue virtually the condition of the switch. Although non a definitive test, it volition serve you every bit an additional cheque for the procedures that follow:

• depress the brake pedal and hold it at that place during the test
• turn the ignition cardinal to the 'Start' position (as if y'all were to commencement the engine) and hold it there
• movement the shift selector through the dissimilar positions
• if the engine starts in a position other than Park or Neutral, most probable the switch needs aligning.
• if the engine starts only in Neutral, probably the switch needs replacement.

If the engine doesn't crank in whatever position, try the adjacent test, first in Park and so in Neutral:

• position the shift selector in Park/Neutral
• turn the key to the Offset position
• jerk the shift selector without moving information technology out of Park/Neutral
• if the vehicle doesn't outset, hold the selector forward (when in Park only) and try to get-go the engine

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If you are able to crank or start the engine, probably the Neutral switch needs to exist adjusted.

Locating the Neutral Switch

The neutral safe switch on an automatic transmission (also known equally a park/neutral position switch or neutral first switch) is usually mounted to 1 side of the shift lever (meridian of the manual), around the base and near the lesser (forepart-wheel bulldoze models); other models have the switch fastened to the left side of the transmission itself (rear-bike drive). The switch is operated by the shift linkage.

If you don't know what the neutral switch looks similar in your vehicle model, hither are three options to know what y'all're looking for:

1. Consult the service manual for your particular motorcar brand and model. If yous don't accept the transmission, look for a copy in the reference section of your local public library. Or, better yet, buy your own copy of the repair manual. You lot'll find an inexpensive aftermarket service manual at most car parts stores or at Amazon. The manual comes with maintenance, troubleshooting and repair procedures for many systems and components, with step-by-footstep directions and photos to make your repairs easy.
2. Visit an machine parts store online and search for the neutral condom switch for your vehicle. Near Web stores provide images or photographs for most items in their itemize. This manner yous'll know what exactly you're looking for.
3. End by an auto parts store in your area and ask them to show you the neutral switch for your particular model. Most of the fourth dimension, they'll also permit you know where you'll detect the switch in your car.

Accessing the Neutral Switch

If your neutral switch is located adjacent to the shift lever:

• Unscrew and lift the function of the console associates surrounding the base of the lever to proceeds admission to the switch. You may need a standard and Phillips screwdrivers and a ratchet for this.

If your switch is mounted on the transmission:

• Park your car on a level surface.
• Raise the front of your vehicle using a floor jack.
• Push button a jack stand up on each side of the car and align them under the frame.
• Lower the vehicle until it rests on the jack stands.
• Apply the parking brakes.
• block the rear wheels with a couple of wooden blocks.

Adjusting the Neutral Switch

Once yous've gained access to the switch, double-check that your transmission is set to Park. Yous may need to apply the following adjusting process or the next, depending on your application.

Adjusting the Switch by Sliding the Switch

1. Loosen the switch's mounting bolts just enough so that you can move the unit sideways. Employ a ratchet and socket of the correct size for this. On some models you may demand a special, inexpensive tool you can discover in most auto part stores.
2. Ask an assistance to turn and concur the ignition fundamental in the start position, as if trying to burn up the engine. Propose your helper to release the key as soon as the engine begins to turn.
3. Then, slide the switch towards the Park or Neutral position.
4. Equally presently as you lot hear the engine cranking, concur the switch in position and tighten upward the mounting screws.
5. Once you accept secured the switch in place, start the engine with the shift lever in Park and again in Neutral to confirm that the switch operates properly.
6. When finished, supercede the console assembly or lower your car off the jack stands.

Depending on your awarding, a neutral safety switch may exist adjusted.

Adjusting the Switch past Aligning the Marks

Refer to the higher up schematic.

• Once you've loosened the switch, locate the basic neutral marker/line to the right or center of the switch, depending on your application.
• Place the shift selector in Neutral.
• On the switch, align the neutral line with the gap/groove inside the lug nut (pivot point) at the lesser of the switch.
• When both lines align lengthwise, tighten the switch just enough to secure the switch in the aligned position.
• Endeavor to start the engine in both Neutral and so in Park

If the engine starts, tighten the switch mounting commodities to the torque specification indicated in your repair manual (usually 48 in-lbs, [5 Nm]); otherwise, try readjusting the switch. If this is not possible, make sure at that place'south a problem in the starting excursion or the switch itself has failed, continue with the post-obit tests.

Trying to adjust the neutral switch may not work. If the vehicle refuses to start, probably the switch has failed or there'southward a problem in the starting excursion. To ostend whether the switch is yet working, do the following test. Y'all may demand to look up the wiring diagram in your repair transmission for the switch connector to identify both the wire where voltage comes in, and the wire where voltage goes out.

Testing the Switch

• Unplug the electrical connector from the neutral switch
• Using a small jumper wire, jump the final of the connector that gets battery power, and the concluding of the connector that leads to the starter solenoid.
• Position the gear selector in Park or Neutral.
• Try to start the engine.

If the engine starts this time, you demand to replace the neutral switch; otherwise, go along with the next test.

Back-Probing the Switch

On some models, it'south possible to back-probe the switch using a test calorie-free or digital multimeter. Using the wiring diagram from your repair manual, locate the wire(s) for the incoming voltage and outgoing voltage to the starter solenoid.

• Hold the ignition key to the 'Start' position.
• Bear on the voltmeter black lead to a good footing. Or connect your examination light to a good ground.
• Back probe the output voltage wire in the switch with the red pb from your voltmeter or your test light probe.
• If the voltmeter readout shows battery voltage, or the test light illuminates, just the engine doesn't offset, the switch is good and the problem is in the rest of the starting circuit.
• If at that place'southward no voltage present, make sure the switch is receiving battery voltage. Back probe the wire where voltage comes into the switch.
• If at that place's no voltage coming in, check that part of the starting circuit; otherwise, replace the switch.

Checking a Transmission Range Sensor

Many newer vehicle models have a transmission range (TR) sensor. The TR sensor tin can exist an analog or digital type. An analog TR sensor tin be checked with an ohmmeter. Follow the instructions in your repair manual to check the appropriate connections and compare the resistance values to the specifications. Checking a digital TR type sensor may require a browse tool. If necessary, consult your repair transmission.

In the next video a neutral safety switch is disassembled. This view can requite you some clues about what tin go wrong with a switch.

iii. Checking a Neutral Switch on a Standard Transmission

On vehicles with a manual transmission the safe switch is usually called a starter/clutch interlock switch. The clutch pedal controls the switch, which closes merely when the clutch pedal is fully depressed to allow the starter motor to operate.

A typical interlock safety switch.

1. First, locate the safety switch. Depending on your particular vehicle brand and model, y'all'll find the switch around the top of the clutch pedal arm or as part of the push rod that connects between the clutch pedal and the brake master cylinder.
2. Unplug the electrical connector from the safety switch.
3. If the connector has two wires, use a small jumper wire to connect both terminals of the connector; if at that place's but one wire, use a jumper wire to connect the terminal of the connector to a good ground.
4. Make sure the transmission is in Neutral.
5. Try to start the engine.

If the engine starts, you lot may need to replace or adjust (adjustable types) the switch. If the engine doesn't first, there could exist a problem with the starting circuit or one of its components.

You can likewise test the switch using a voltmeter:

1. Set up your DMM voltmeter to test for continuity — usually the everyman range on the Ohms scale. If your voltmeter doesn't come with a continuity feature, just set you meter to the everyman resistance range.
2. Unplug the switch electrical connector.
3. Plow on your voltmeter and bear upon one lead to one terminal on the switch and the other pb to the other last.
4. Your voltmeter should non beep, indicating at that place's no continuity. Alternatively, the display on the meter should indicate infinity (OL) resistance. If so, continue with the next footstep.
   • If there's continuity or at that place'due south a minimum of resistance — usually in the thousandths — supplant the safe switch
   • If you have an adaptable type switch, try to adjust it post-obit the procedure described in your repair transmission. Then, echo steps 2 and 3. If the switch passed this test, continue with the next steps
5. Echo step 3. This time, though, go on the clutch pedal fully depressed.
6. Now, your voltmeter should beep indicating continuity. Alternatively, your meter's readout should indicate minimum resistance; otherwise, supervene upon the switch.
   • Notwithstanding, if there's no continuity and yous have an adjustable switch — bank check your repair transmission — try to adapt information technology and repeat stride five.

The next video shows a unproblematic manner to backprobe a clutch interlock switch.

4. What if My Switch Tests Okay?

A neutral safety switch out of alignment or worn out is not uncommon. Operation of the shift selector, vibration during engine performance, and dealing with road imperfections while moving down the road, all create the ideal conditions for the shift linkage to wear down and for the neutral switch to come loose and go out of alignment or fail. If you have an automatic transmission and the switch seems to be operating properly, check the shift linkage. On manual transmissions, if your interlock switch seems to be working properly, nigh probable the problem is with the starting circuit or one of its components.

Examination Your Knowledge of Neutral Safety Switches

For each question, choose the all-time answer. The answer primal is below.

1. What is the purpose of a neutral switch?
   • To start the engine when the ignition system fails
   • To provide a spark to the combustion chambers
   • To keep y'all from starting the engine in gear
   • To prime number the fuel system to fire up the engine
2. All of these are possible symptoms of a bad neutral safety switch EXCEPT:
   • Your backup lights don't come on when y'all support.
   • Your vehicle starts in a gear other than Park or Neutral.
   • Your clutch slips on hills.
   • Your vehicle won't start at all.
3. On a manual manual, the role of the neutral safety switch is played past:
   • The throwout begetting
   • The clutch interlock switch
   • The airplane pilot bearing
   • The 02 sensor

Answer Key

1. To keep you from starting the engine in gear
2. Your clutch slips on hills.
3. The clutch interlock switch

This article is accurate and truthful to the best of the author's knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business organization, financial, legal, or technical matters.

Questions & Answers

Question: The neutral safe switch is inside the transmission on the Allison transmission. Is in that location away to bypass information technology to become the vehicle to a repair shop?

Answer: You may exist referring to the neutral start back up (NSBU) switch. This one works in conjunction with the neutral safety switch. The NSBU mounts in the valve torso of the transmission. Replacing the neutral safety switch might non be such a hassle. If that'southward what you demand to replace, you lot may desire to try consulting your repair transmission. I think you may be able to supplant information technology yourself. The NSBU is used by the reckoner to confirm the transmission is in Neutral or Park to appoint the starter motor. If the NSBU has failed, you lot may want to try providing ability directly to the starter to fire up the engine. Then drive to the shop to supervene upon the switch.

Question: I'one thousand testing a neutral switch on a 2004 Jeep Grand Cherokee. Is a replacement required? If so, is it an expensive repair or fifty-fifty necessary?

Answer: Old yous tin remove the cover plate and make clean the contacts and have it running for some fourth dimension. But they wear out and are bound to give you problems again. It'southward not also expensive and probably you lot tin practise information technology yourself following the process in your vehicle repair manual.

Question: I changed my neutral safe switch that took the check engine low-cal off. Information technology's adjusted correct as far equally I know because it starts and drives and everything. But today I had an incident where I collection it for like one-half an hour, put it in Park, and when I came back out, information technology wouldn't release out of Park, and I'chiliad kind of baffled by that. I'grand wondering what information technology is?

Respond: Probably the shift interlock is stuck. Make sure the cardinal is in the On position. Possibly your car (if pre-2009, and for sure 2022 and newer) has another interlock in the brake. Make sure to depress the restriction pedal when trying to start the car. Another possibility is the shift interlock solenoid.

You lot may try using the shift lock override. Ready the emergency brakes, ready the ignition central to the On position.

The shift lock override slot is located virtually the shift lever on the console. Insert a minor screwdriver and push the lock and hold information technology there. Step on the restriction pedal, now try releasing the shift lever using the release button. Try starting the engine in Neutral.

You lot may detect some videos that tin can assist yous with this too:

https://world wide web.youtube.com/watch?v=fayeJXj2njA

Question: I'm replacing the NSS on my 993 G Prix LE with a new 1 that's pinned in neutral. Only with the floor shifter in neutral, the new switch doesn't line up with the flats or the mounting holes. What's the problem?

Answer: Sorry, I don't have the manual to give you lot an specific answer. On some models, the switch slides over the selector shaft – Possibly with the transmission in Park. The plastic bushing inside may have to rotate counterclockwise. Simply cheque the instructions in your repair manual. If you lot don't take the manual, your local public library may have a copy in the reference section.

Question: Exercise both the park neutral switch screws demand to be in earlier it works right?

Answer: Once the switch is properly fix in identify, they should concur the switch in position; otherwise, it may non signal the transmission correctly.

Question: I had a check engine light ON on my Kia Sorento 2022 due to a transmission sensor failure. I have replaced the transmission switch. That took the CEL off. Everything is working fine but I discovered accidentally that the engine cranks fifty-fifty in R or D position. Why would at that place exist no sign of switch failure at all in my Kia Sorento?

Answer: The safety switch might've moved from its original position. Sometimes it'southward piece of cake just to lose the mounting bolts and adjust the switch and then that it starts in Park and Neutral. Run across if y'all tin can follow the steps in the mail. Otherwise, you'll need the repair transmission for your particular model.

© 2022 Dan Ferrell

Source: https://axleaddict.com/auto-repair/How-to-Adjust-a-Neutral-Switch

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