Converting from Manual to Auto. How to wire in Neutral safety?

[broncoP]

Just installed a auto, was a manual with manual wiring harness. Have the neutral safety with wiring and plug coming out from tranny. What wires do you use from the neutral safety(4 wires) and where do they go
Thanks

 

[rguest3]

Those 4 wires will go to the Neutral safety/Reverse switch on the automatic. C4 has a switch on the driver's side.

 

[DirtDonk]

Which auto trans? What year is your Bronco?
If a '72 or older, the two Red w/black stripe wires for the backup lights will connect to the same color wires near the base of your steering column under the master cylinder. You can extend them, or you might not need to.
Does not matter which one goes to which, since it's just an open/close switch.

The Red w/blue wires coming off of your switch are just as simple, but will be a little trickier simply because of the greater distance to the pieces they effect.
On the starter relay/solenoid there is a Red w/blue wire (small one on the "S" post) which comes directly from the ignition switch. Somewhere between the ignition switch and the starter relay you need to cut that wire and connect one side to one wire on the safety switch, and the other to the other wire from the switch.
Here again, does not matter which one connects to which, since it simply breaks or makes contact in the circuit.

Doing that will keep your starter from spinning in anything but Park or Neutral.
If your Bronco is a '73 or later model, there is already a square 4-wire plug behind the engine that all these things connect to. When a manual trans is present, the Red w/blue wire side of the plug has a jumper wire, or loop. Either way you'll likely have to fiddle with that connector a bit to make things work with the auto, but it should be pretty straightforward.

Good luck.

Paul

 

[broncoP]

Which auto trans? What year is your Bronco?
If a '72 or older, the two Red w/black stripe wires for the backup lights will connect to the same color wires near the base of your steering column under the master cylinder. You can extend them, or you might not need to.
Does not matter which one goes to which, since it's just an open/close switch.

The Red w/blue wires coming off of your switch are just as simple, but will be a little trickier simply because of the greater distance to the pieces they effect.
On the starter relay/solenoid there is a Red w/blue wire (small one on the "S" post) which comes directly from the ignition switch. Somewhere between the ignition switch and the starter relay you need to cut that wire and connect one side to one wire on the safety switch, and the other to the other wire from the switch.
Here again, does not matter which one connects to which, since it simply breaks or makes contact in the circuit.

Doing that will keep your starter from spinning in anything but Park or Neutral.
If your Bronco is a '73 or later model, there is already a square 4-wire plug behind the engine that all these things connect to. When a manual trans is present, the Red w/blue wire side of the plug has a jumper wire, or loop. Either way you'll likely have to fiddle with that connector a bit to make things work with the auto, but it should be pretty straightforward.

Good luck.

Paul

Great info, thanks. It's a 73 or 74

 

[DirtDonk]

Then you likely just need to simply separate the two halves of the connector at the firewall (I think it's close to dead center behind the intake, near any vacuum trees) and connect the one from the NSS on the side of the trans.
In that case, in theory at least, everything should work without doing any re-wiring.

Please let us know if that works out.

Paul

 

[broncoP]

Then you likely just need to simply separate the two halves of the connector at the firewall (I think it's close to dead center behind the intake, near any vacuum trees) and connect the one from the NSS on the side of the trans.
In that case, in theory at least, everything should work without doing any re-wiring.

Please let us know if that works out.

Paul

Just plugged in NSS, that part was easy, you're right, plug and play . I'm gonna start it in few days and let you know.

 

[broncoP]

Anywhere other end of vacuum modulator line should go in particular, back of intake?

 

[Steve83]

This & the NEXT few show the wiring:


(phone app link)

The vacuum line goes to the intake manifold. Any available nipple that it fits should be fine. But you still haven't said which trans you installed. You should put ALL the truck's details into your signature, like Paul's. %)

 

[broncoP]

This & the NEXT few show the wiring:


(phone app link)

The vacuum line goes to the intake manifold. Any available nipple that it fits should be fine. But you still haven't said which trans you installed. You should put ALL the truck's details into your signature, like Paul's. %)

It's a C4. It's not my truck just doing a bunch of work on one for a buddy. I should update my sig for my truck tho

 

[gddyap]

It will work without the neutral safety switch too. It just means you have to know it will start in gear like a manual. Both of mine are set up that way. Also, when the engine starts, if you don't have the brakes applied, it'll take off quick.

 

[DirtDonk]

And tell your buddy not to throw away that old connector. There are people who would buy it because their NSS jumper wire has failed and they'd rather not hack in a new jumper.

Paul