How To Test and Replace the Neutral Safety Swtich / Inhibitor Switch P0705

welcome to another episode guys you know

I've had a lot of questions regarding

the neutral safety switch or the

inhibitor switch and how do you in fact

test the switch itself I do have a video

uploaded showing how to replace the

switch but when I shot that it was

during the winter time there was snow on

the ground and I just didn't have enough

time to go ahead and test or show you

how to test the sensor itself but today

I will show that we'll go ahead and go

through how you can test the the

inhibitor switch and all that you need

is a multimeter and essentially what

we'll be doing is looking to see if we

have continuity continuity just means

that there's an electrical connection

between two points if we don't have any

continuity then there's a break

somewhere in that connection and you

need to replace the sensor so that being

said let's go ahead and let's begin all

right now the neutral safety switch is

located toward the bottom

it's toward the front of the vehicle

this happens to be a Nissan Maxima in

1887 but on this vehicle is toward the

bottom on the driver's side last time I

shot this video that was snow on the

ground and this is the way that I got to

it however today we have the car in the

garage and it is quicker if you obtain

or get access to the switch right here

now this is a plastic cover and you have

a couple of screws holding it on so I'm

going to remove this cover and we'll

have quick access to the sensor now once

you remove that plastic tab this is what

you're going to see this happens to be

the transmission and right in the front

right here this is the inhibitor switch

and of course you have a this is the

gear selector so in fact when you change

when you put the vehicle from reverse to

neutral to drive this whole system this

whole lever is moving and the sensor

really the whole point about this sensor

is to make sure that the car doesn't

crank while it's in Reverse or drive or

drive it will only allow the

car to crank and park in neutral so if

this sensor starts to go your car may

not crank at all because the sensor has

no idea what gear you're in or the

sensor thinks you're in a reverse or

forward gear so what I'm going to do

I'll clean up the top of the motor

because there are two electrical

harnesses and they lead up toward the

engine bay and there's so much clutter

up there that you won't clearly see what

we have to do so I'll clean up the top

in fact if you're curious what I'm doing

just take a look I'll include a link

right now for the first video that I've

uploaded and I show in detail how to

clear at the whole top of the engine if

you're curious but anyway I'll clear at

the top we'll have clear access to these

harnesses and then we can go ahead and

start the testing okay so everything is

cleaned out here if you take a look

these are the two harnesses that lead to

the sensor there's your sensor right

down there so let's go ahead and unplug

these two sensors these harnesses OOP

sorry about that we're going to unplug

these two harnesses right here and then

let's do the continuity testing so you

press down the tab here and these things

keep it really tight just enough force

there you go since your first one you

have another one right here and there

you go so now we need to check or do our

testing from these terminals because of

course these harnesses lead to the

sensor this goes toward the computer of

the vehicle we're not concerned about

this right now we just want to make sure

that the sensor is okay now once you

disconnect those two harnesses go ahead

and also disconnect the shift boot

leading to the sensor and I'll show you

in a minute why does it really want to

do this but just go ahead

and remove this right from the sensor

okay now this is free and clear and I'll

show you why you really need to do that

the next step is we need the multimeter

specifically we need the ohm setting now

if you've never used a multimeter

they're pretty simple to use in this

case again we need the ohm setting let

me just get my leads a free here so as

you can see we have a black and a red

wire and you have three inputs in this

case so in this case we have the black

wire going to the black input and then

you have red wire which would either go

to the 10 amp or you have volts ohms and

milliamps in this case since we're doing

ohms we lead it to that input all right

so again we need the ohm setting and we

need the audible this audible selection

here as you can see it gives you that

this marking letting you know that

you're on that you are on a an audible

setting so if you cross a batteries a

little low here but the cross is two

leads here you have an audible alarm

letting you know that you've completed a

circuit or you have continuity in other

words so that's what we need to test on

these harnesses so let's go ahead and do

that so let's go ahead and zoom in here

let's start with this first one this

only has two leads coming out out of

this harness and just go ahead make a

connection let me just make sure you

guys can see this make your connection

and we should have continuity which we

do as you can hear so this harness is in

good shape it's working correctly

now for the second harness this is a

little bit more involved first step is

we need to make sure that the inhibitor

switches in the

position so I'll include a picture right

now and on the upper right hand side of

the screen to showing that the inhibitor

switch is in the park position then what

we need to do is check terminals three

and four now that happens to be the top

left and the bottom left on this vehicle

now really to do this test obtain the

factory repair manual for your vehicle

because every card is different you can

do this by trial and error but really

get the repair manual for your car just

because you can essentially do any

repair and including this one so we'll

do terminal three and terminal four and

we have continuity now another way you

can test this if you don't have a

factory repair manual you could do trial

and error in other words let's say I

have no idea which two points to touch

if I just start going along here you

don't hear anything at all and that's

because only two points make continuity

in the park position okay so these two

points not a this point nothing this

point nothing but when I get to the

bottom there is continuity so I know

that this happens to be for park so this

is working correctly now the next step

is to check the reverse position so

we'll remove the excuse me we'll move

the inhibitor switch to the reverse

position and then we'll check terminals

three and terminals five park into

reverse all right so we're in the

reverse position so Terminal three is

always on the upper left here on this

vehicle and Terminal five happens to be

on the bottom as well so here we go and

we have continuity again if you touch

anything else you won't hear anything

but if you touch Terminal three in this

case and Terminal five it works so

continue to do this test through neutral

Drive second first gear and see if we

gain continuity throughout all gears and

you should now one other thing you could

do is reattach

the control cable back onto the sensor

and then check for continuity and you

want to make sure they still have

continuity once that control cable is

reattached to the sensor then get on the

vehicle put the vehicle into reverse and

check for continuity and then get back

in the car put the car put the gear

lever into neutral and then check for

continuity and so forth and do that

throughout the gears this is just a

safety check to make sure that that the

control cable is properly adjusted now

if you're not getting continuity here

then go ahead and just adjust the the

control cable now one more thing before

we wrap this up this is in regards to

sometimes if you try to crank the car or

start your car and nothing happens in

Park and if you shift it into neutral

and the car cranks sometimes you just

need an adjustment and in other words

you want to make sure that that this

lever or this lever here is in alignment

with the sensor now to do that it's

pretty simple what you want to do let me

just get a ratchet here first you just

need to loosen up the three nuts holding

on the sensor here so just loosen them

up these happen to be a 5/16 of an inch

and there's another one oh you got put

this in neutral okay make sure it's in

neutral right here just watch your

fingers all right that's good enough now

what you need to do is I'm going to use

a an allen key if you have a pin that

will also work on top here you just

place a pen or a nail and key and you

want to make a contact book you want to

make contact with this other lever right


and this essentially aligns everything


when you start the car the vehicle knows

that you really are in park and it will

allow you to start the vehicle if these

two points are off sometimes you have to

shake the the the transmission lever and

then the car will crack and that's just

because these two points are not exactly

in sync with each other so just go ahead

and also check this as well and then

what I like to do is we'll keep this the

pain or allen wrench or allen key

whatever you're using keep it in place

and just tighten everything back down