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Neutral safety switch

VanWelder

Newbie
Joined
Mar 13, 2018
Messages
36
Hello,
Did 76 Bronco come with a neutral safety switch on models with 3 speed manual on the column?
Thanks,
Butch
 

DirtDonk

Contributor
Bronco Guru
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Nov 3, 2003
Messages
49,369
Hey Butch. No they did not have the switch. But they still had the wiring and connector for it. After '73 all EB's had that 4-wire connector behind the engine near the firewall.

On manual trucks there is simply a short jumper wire of the same color (Red w/blue) jumpered between the two START wires that would normally work with an auto trans NSS.

Paul
 

DirtDonk

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Are you having trouble starting yours? Giving you an intermittent issue maybe?
If so check that jumper wire. They're super reliable, but they're not at least 44 years old and we've been seeing failures more and more for the past ten years or so.

You can test by replacing the jumper with a known good piece of wire temporarily, or if you have the luxury of a ready helper you can test for voltage at the various places.
One of the Red w/blue wires should read 12v with the key in the START position only. If it does, then move up the line until you find out where the power stops.
If you do not see 12v at either wire in START, then the problem lies either with the ignition switch, or the section of Red w/blue wire between the key and the engine compartment connector.

Paul
 
OP
OP
V

VanWelder

Newbie
Joined
Mar 13, 2018
Messages
36
It starts just fine. I’m looking to not accidentally start it in gear.
This is the bronco you helped me with regarding the turn signals. I have a 68 with a 289 and 3 speed on the column. I integrated a 76 harness that was fora 302 with a C4 automatic transmission. I jump the NSS plug to start it. I was just wondering if I could hook it up to a proper Ford switch if the 76 came with one.
Butch
 

DirtDonk

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What you would want would be more of a "clutch interlock switch" instead. Still lets you start in any gear, but only if you have the clutch depressed.
A neutral safety switch is possible with some manual transmissions, but not very many I don't think. Certainly not with a stock 3-speed and shifter. Much easier to use the clutch.

A basic normally-closed plunger switch like a brake switch (they're available either normally-open or normally-closed with the same body design) on a simple bracket so that it breaks the start circuit until the clutch is depressed would be pretty straightforward. Especially with the '76 harness already having that connector.
Instead of your jumper wire, you run that new switch between one side of the connector and the other.

Paul
 

Digitalcopier

Newbie
Joined
Nov 14, 2021
Messages
5
hi Everyone i have a 1967 i upgraded to a 302 and a C4 automatic and trying to install the neutral safety switch but i do not know where are the conectors plug or is there a place where i can buy a hardness
 

DirtDonk

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Messages
49,369
Just to be sure, is the C4 the type that mounts the neutral safety switch to the side of the case, where the shift shaft comes out? I think some early cars had a different setup, but Broncos always had theirs on the side of the transmission body.

The half of the harness that is connected to the switch is actually part of the switch and comes with a new one. If you have an old switch where the wires are missing, you'll need a new one, or create your own.

Next, the '67 would not have come with anything like that for the body side of the harness since the automatic was not available until '73 model year. After that the harness was integrated whether you had the manual or automatic. But before that, like in your case, you'll have to create your own. No existing harness exists that you can buy off the shelf, that I'm aware of.
Any replacement harness for the vehicle, which are finally becoming available, would not include the proper connections because too many changes were made between '71 and later models to fit your existing harness.

You'll need to run extension wires from your existing backup lamp switch wires (Black with a red stripe I think) mounted on the lower end of the steering column (visible just below the brake master cylinder) over to the wires of the same color on the new neutral safety switch. Does not matter which goes to which, as long as they're the same colors.
With that simple extension your backup lamps should work.

For the actual "neutral safety" aspect of the switch, you'll need to find your Red w/blue wire coming out of the firewall, cut it long enough to reach the switch wires of the same color (or add an extension) and make an extension for the other half of that wire to the other wire of the same color (Red w/blue) on the neutral safety switch.
One half of that wire comes from the ignition switch and the other half goes to the starter relay/solenoid. By cutting this wire and connecting it through the new NSS you have given yourself the safety of not starting in gear.

The NSS will have it's own 4-wire connector on the end. Since you don't have one on your body side wiring, you might as well cut it off of the switch wiring and make your own connector. I use GM Weatherpack connectors available at most parts stores, but you can use anything you want.
The original connector resembles a 4-wire universal (trailer) wiring plug (not the Flat-4 you see on the bumper) that is available through many sources. I think those are keyed wrong for the Ford version, but you could still use one of those if you don't want to go with Weatherpacks.

Hope that helps.

Paul
 

DirtDonk

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And I see you've been here six months, but since it's your first post I'll still say "welcome" to classicbroncos anyway!:)

paul
 

TomandEthan

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Dec 14, 2020
Messages
12
I have an ax15 manual tran. and looking for a "clutch interlock switch" . Any recommendations ?
 

DirtDonk

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I don’t know of any kits, but you can rig up your own as described above.
The type of transmission would not always matter unless it already came equipped with one from the factory. Which I don’t think the AX did?
Since the clutch is independent of the transmission, you’ll have to use the clutch linkage as your device location.
I don’t remember reading hear of anyone actually ever doing it. But it may have happened in the daytime. Anybody out there got one that they’ve worked on?
Or maybe pictures of an existing factory one?
I know Toyota did that on their four-wheel-drive trucks, and then they even offered a dash mounted defeat switch so that you could still start it in gear with the clutch out if desired when four-wheeling.
 

DirtDonk

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There is one other possibility I think. It’s not perfect, but it would be of some use to some people.
Use the reverse light switch on the transmission as your neutral safety switch. You could use it in such a way that the vehicle would only start when the transmission was put into reverse.
The downside to that is that it would still let you start with the clutch out.
 

56f100bbw

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Feb 3, 2008
Messages
2,354
Loc.
Tucson / lakeside AZ
On my 66 mustang fastback 4 speed I mounted this switch on the firewall made a bracket so when the clutch pedal arm hits the switch on the floor it will start ,I am not finished with it yet sorry I don’t have a pictures of it mounted
 

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jamesroney

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Sep 11, 2007
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Fremont, CA
I don’t know of any kits, but you can rig up your own as described above.
The type of transmission would not always matter unless it already came equipped with one from the factory. Which I don’t think the AX did?
Since the clutch is independent of the transmission, you’ll have to use the clutch linkage as your device location.
I don’t remember reading hear of anyone actually ever doing it. But it may have happened in the daytime. Anybody out there got one that they’ve worked on?
Or maybe pictures of an existing factory one?
I know Toyota did that on their four-wheel-drive trucks, and then they even offered a dash mounted defeat switch so that you could still start it in gear with the clutch out if desired when four-wheeling.
Every 1997-2006 Jeep Wrangler with the AX15 (or NV3550 or NSG370) came equipped with a Clutch Switch. (note that I did not call it a "safety" switch.) Every 1997-2006 Jeep Wrangler also came with specific instructions and a convenient way to defeat that switch. Just have to move a fuse! The YJ with the AX15 did NOT have a clutch interlock switch.

The AX15 has a Neutral Drive Switch to inform the ECU that it is in Neutral. The clutch interlock switch also has a circuit to inform the ECU. This prompts the ECU to enter the "neutral" engine management strategy. One could easily wire the AX15 Neutral Drive switch into the start circuit. Then it would only crank if the stick is in Neutral.
 

ngsd

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Why couldn't you repurpose and wire a brake light switch on the clutch pedal like the brake pedal?
 

Speedrdr

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Nov 27, 2017
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Paris, MS
I’ve been driving a manual gearbox of some type for over…let’s just say 100 octane leaded gas was 43 cents a gallon. I’ve got experience. You either mash the clutch to the floor and hold it there or make dang sure you know where neutral gate is. Why in the world search for a solution where there’s not a problem??? But that’s just my take on it. Everybody has their own way.

Randy
 

Digitalcopier

Newbie
Joined
Nov 14, 2021
Messages
5
what is the best and easiest transmission to install on a 302 that it has a manual 3 speed right now?

the 302 purchased from blue monkey and also put a Holley Sniper EFI need suggestions and prices or if someone has one that is in good condition i will be willing to buy it
 

ngsd

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Bronco Guru
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Mar 2, 2019
Messages
2,613
what is the best and easiest transmission to install on a 302 that it has a manual 3 speed right now?

the 302 purchased from blue monkey and also put a Holley Sniper EFI need suggestions and prices or if someone has one that is in good condition i will be willing to buy it
The AX15 is the best swap in my opinion. I am on my third one and love them. You can buy a complete kit.
 
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