What in the hell does the neutral switch do?
 

I've searched through this forum and found lots of references to the neutral safety switch, as though everyone but me already knows what the dang thing does, but nowhere have I found it spelled out.

What does the neutral switch do, and what is it for?

I ask because I recently replaced my destroyed tranny with one I bought online and had rebuilt, and the wires on the neutral switch weren't long enough to reach the connectors. I finally got under there and did some cutting, soldering, and heat-shrink-tubing treatment to make the connection happen properly. There was absolutely zero difference between before and after. My car has always started just fine (except when flooded), and idle has never been an issue for me.

One time a long time ago, the RPMs would go way up in neutral, but in gear they would drop back to idle speed. This was with the clutch diengaged in both cases. It hasn't happened again ever.

If anyone can enlighten me, I would be most appreciative. Thanks!

i know alarms use the neutral switch, so you can only use remote start when the car is in neutral, not in gear. not sure what other function there is.

The online fsm, 89 model, Fuel section, page F1-76, RELATIONSHIP CHART, says it effects the fuel injection amount, fuel pump resistor relay, A/C relay, split air solenoid valve, switching solenoid valve, relief solenoid valve, AWS solenoid valve, pressure regulating solenoid valve, bac, VDI, 6 port injection, lead and trail timing.

Outside of that, it does not very much. The above is for a 89model. Your model may vary. Its a free manual. Still online. Cost not much.

On the S4 models the ECU uses it to control idle on start-up as well as I am sure that all the things hailers mentions.

Hmmmmmmmmmmm..............
 

So is it really a true dependable nuetral safety switch cause I am thinking remote start like my last car, only this time it won`t drive away with me chasing it down the...........I would rather not talk about that day.

:o:

John 88 vert.

I'm sorry John... I hope it wasn't as bad as the picture my imagination is painting. That would funny as hell to an outside observer though :D

Does anyone know those wire colors that plug into the neutral switch?

Green/Black
and Black

on an average symetrical rectangle plug for the 88 model.

It happened twice actually, the first time was right after install and I told my girlfreind (now my wife), "hey watch this" and tried to impress with auto start but since it was in first it simply started pushing my room,ates car and my neighbors car like a train until I got the door unlocked....(yes, AUTO lock too), and hit the brake pedal to shut down. Then the second time was me trying to start and leave my work and it started and drove about 10 feet into the ditch in front of it, kinda looked like the black TII ditch wreck pic floating around this site lately.

Still funny, luckily I have a sense of humor and noone was killed,

John

P.S. Thank God they got the snipers finally, but it proves that a father and son CAN find common interests these days, and spend time together.

never ever do a remote start on a manual tranny car that does not have a nuetral safety

Mazda, ford and some nissans have them.

My manual tranny 'vert has remote start. The nice thing about that wire is that it will not let the remote start even turn on unless the car is in neutral or the clutch is pressed in.

I recently 'fixed' my neutral switch. The pins inside the white connector (adjacent the transmission) were bent and not making contact with the receptacle side. After I fixed that, my 'neutral' idle is 100 rpm higher than 'in gear' idle.
The ECU will also send the car to the 3500 rpm cold startup when it 'senses' the trans is in neutral.

Curtis
'86 GXL autox'r

I wish my Mitsu Conquest would have had that so it did`nt drive off on me.

:mad: :mad:

The neutral switch in the transmission is also used to turn the cruise control off if the transmission is shifted out of gear.

cluosborne.....yes, in spades to what you said about the cold startup being effected. I've got a part time neutral switch in my turboii that has been screwing with my 3000rpm startup. I can put a meter on the wire at the ECU and make it make/break by bumping the shifter. Someday I'll get around to fixing it. No rush.

This is good info. Does anyone have a digital camera who can take a picture of those wires so I can see what the shape of the connectors are?

When I bought the car, it was my first car ever, and all I knew is that the reverse lights weren't working. Now, 2½ years later and 2½ years wiser in the ways of RX-7s, I learned that's because someone majorly f*'ed with the wiring down there.

What I've done so far is put a new (rebuilt) manual tranny in there, gotten good switches for reverse and neutral, but the electrical functions still aren't happening.

I'm almost done fixing the reverse lights, I've narrowed the problem to somewhere between the output wire from the reverse switch and the wiring harness next to the fuse box. Will get under there tomorrow morning and fix it all the way, even if I have to run my own wiring to get the reverse lights to come on when I shift into reverse.

Neutral though, I have no clue what's up with that. I know the switch is good, I tested it for continuity with a multimeter, and it worked perfectly when the little nipple-button was pressed. But it was used, given to me for free from a wholesale tranmission parts warehouse, and it was interchangeable with the reverse switch as far as screwing into the side of the transmission. The guy said it was a neutral switch, so I just believed him and plugged it into the wires with matching plugs on them (2 separate male/female connections, but the kind you have to hold down a tab on the side of the white plastic connector to unplug it, and set up so you can't interchange the 2 connections).

Now I'm thinking I may have everything ass-backwards. The reverse switch I got (used, free from a transmission repair shop) had only 2 wires instead of 4 coming out if it. That's ok, I don't give a crap about the "Shift Up" light at all, unless the 5th gear switch does anything besides keeping the upshift light from coming on? The connectors on the end of those 2 wires on my reverse switch fit the wires that are colored like what the FSM says the wires for the reverse lights are (2 separate straight male/female connections). If I had a digicam I'd show you, but my poor broke ass is unemployed in Oregon right now, and it's impossible to find a decent job here right now. Anyway, because there're no wires from the 5th gear switch, there's a plastic 2-wire connector harness under there that's not connected to anything. It's all one piece and oval shaped, about half an inch across the long way. Could that be what my problem is? Could those be the real neutral switch wires and I just have the 5th gear switch wires plugged into my neutral switch? If so, that would entirely consistent with what's going on. If the car was in neutral, and it's activating the wires for the 5th gear switch, then I wouldn't see anything going on at all. For one, I have my girlfriend's picture in front of the upshift light, and two, I removed the bulb. If this long-winded post makes sense, let me know. If not, let me know. Thanks!

This is good info. Does anyone have a digital camera who can take a picture of those wires so I can see what the shape of the connectors are?

When I bought the car, it was my first car ever, and all I knew is that the reverse lights weren't working. Now, 2½ years later and 2½ years wiser in the ways of RX-7s, I learned that's because someone majorly f*'ed with the wiring down there.

What I've done so far is put a new (rebuilt) manual tranny in there, gotten good switches for reverse and neutral, but the electrical functions still aren't happening.

I'm almost done fixing the reverse lights, I've narrowed the problem to somewhere between the output wire from the reverse switch and the wiring harness next to the fuse box. Will get under there tomorrow morning and fix it all the way, even if I have to run my own wiring to get the reverse lights to come on when I shift into reverse.

Neutral though, I have no clue what's up with that. I know the switch is good, I tested it for continuity with a multimeter, and it worked perfectly when the little nipple-button was pressed. But it was used, given to me for free from a wholesale tranmission parts warehouse, and it was interchangeable with the reverse switch as far as screwing into the side of the transmission. The guy said it was a neutral switch, so I just believed him and plugged it into the wires with matching plugs on them (2 separate male/female connections, but the kind you have to hold down a tab on the side of the white plastic connector to unplug it, and set up so you can't interchange the 2 connections).

Now I'm thinking I may have everything ass-backwards. The reverse switch I got (used, free from a transmission repair shop) had only 2 wires instead of 4 coming out if it. That's ok, I don't give a crap about the "Shift Up" light at all, unless the 5th gear switch does anything besides keeping the upshift light from coming on? The connectors on the end of those 2 wires on my reverse switch fit the wires that are colored like what the FSM says the wires for the reverse lights are (2 separate straight male/female connections). If I had a digicam I'd show you, but my poor broke ass is unemployed in Oregon right now, and it's impossible to find a decent job here right now. Anyway, because there're no wires from the 5th gear switch, there's a plastic 2-wire connector harness under there that's not connected to anything. It's all one piece and oval shaped, about half an inch across the long way. Could that be what my problem is? Could those be the real neutral switch wires and I just have the 5th gear switch wires plugged into my neutral switch? If so, that would entirely consistent with what's going on. If the car was in neutral, and it's activating the wires for the 5th gear switch, then I wouldn't see anything going on at all. For one, I have my girlfriend's picture in front of the upshift light, and two, I removed the bulb. If this long-winded post makes sense, let me know. If not, let me know. Thanks!

When I was installing them, I wouldnt even put one on a manual tranny car unless they signed a waiver :) I did one on a Tercel once, and he had to have 4 people pick it up off the parking stump at taco bell LOL

One of these days I'll have to tell you the story of the 3000GT that one shop did, that left through the closed bay door, before the cust could even pick it up

Ah the good ol days of tint/stereo shop jobs, I kinda miss the biz sometimes.

John

Not me...

I just miss some of the hanging out working on my own car, in my job now as a field tech, I work by myself and basicly work alone without seeing another employee for a week or so at a time. Makes for a real lonely X-mas party.....BUT since my manager is in the next state, I can pretty much work 25-30 hours, log it in like 40 and goof off all I want. So I don`t really miss WORKING there just the hanging out and bs`ing part.

John

P.S. back on the nuetral safety switch thing I guess mine works I have noticed that the RPM does go up to around 2800 and instantly drops when I put it in any gear.

pretty cool, time for a remote start baby!!

J

Hey is anyone gonna answer my question? I had a big long post about what I think is wrong with my neutral safety switch issue, and no one's responded. Anyone with any knowledge on this would be much appreciated. Thanks.

Hey MoJo
It's hard to tell what your configuration should be when we don't know year / model you have!
The connector for my '86 is one piece, 2 wires / 2 pins in a white oval housing. So, maybe you are wired to the wrong leads. I know the first gens have individual connectors for the wires.
Check with a multimeter that the switch leads go 'continuous' when in neutral. I mean check on the car, so you know the nipple is seating in the groove on the control rod. If the switch checks out OK, hook up your leads, and check the pin at the ECU. I can't remember the pin #, might be 2C, but check a wiring diagram. You should get ground in neutral, and open in any gear. If you have problems, trace along the harness and connectors. That's how I found the bent pins in my connector.

Curtis
'86 GXL autox'r

Oops, sorry about that. I have a 1987 NA. Does that help?

1G is for the neutral switch. 2C is the ground for a group of sensors.