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Item Posts    Sort Order

Wiring Neutral Safety Switch

 
n1611f
New User
Posts: 2
Joined: 03/13
Posted: 03/22/13 09:49 AM

My 1966 Mustang originally had a manual transmission, when I purchased it the transmission had been changed to a C4 auto., with no neutral safety switch.  I have installed the switch but need to know the color codes on original wires, under the dash, where you can splice the wires coming from the neutral safety switch.  

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waynep71222
Enthusiast
Posts: 455
Joined: 04/12
Posted: 03/22/13 12:12 PM

do you have the back up light and neutral safety switch harness.. they are available and make this a PLUG and play swap..

this harness pushes thru from the inside of the firewall to the engine side.. where the offset connectors hook up to the wiring harness from the side of the transmission...

Neutralsafetyswitchharness

this is a 67 diagram.. see where the red and blue wires turn right to pass to the 4 pin connector for the neutral safety switch.. thats where the harness installs

67Stangcolorwiringdiagram





Mustang Starting System5



there is one important thing...

the wiring harness from the neutral safety switch needs to be clamped to the side of the transmission so it does NOT wiggle around in the air flow... if it does.. it will have a very short life span of a few months to a year or so... as the wires will fatigue and break...

Fordc4neutralsafetyswitchadjustment


you can see the clip in this image.. on the upper left servo cover bolt... the wire is NOT properly installed in this clip...

Fordc4 Neutraleafetyswitch  

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n1611f
New User
Posts: 2
Joined: 03/13
Posted: 03/22/13 01:24 PM

I have the exact harness you show in the photo.  I will follow the diagram and we will see what happens.  Thanks, I will keep you posted.  

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momsmustang8
New User
Posts: 2
Joined: 09/13
Posted: 09/24/13 06:01 PM

The picture and the drawing have the wiring clip in different places. Which one is correct?  

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waynep712222
User
Posts: 223
Joined: 04/13
Posted: 09/24/13 10:44 PM

Icon Quotemomsmustang8:
The picture and the drawing have the wiring clip in different places. Which one is correct?

that i don't know.. i usually find them in the upper position..  but there are dozens of models and years that i have not worked on..

i do know that the air flow under the car.. is enough to move that harness around...

and over the years... that harness flapping uncontrolled will break the insulation off right at the neutral safety switch first..  usually resulting in a car that the engine cranks when you turn the key to the ON position..  

this is because the power wire to the switch for the back up lights circuit.. is next to the wire from the switch to the starter solenoid S terminal are next to each other..  once in a while they are switched.. so as you pass thru  reverse. the starter engaged...


i can explain why there is a difference...

with the clip in the upper location..  the wiring harness passes down from the firewall over the transmission and to the top clip...

with the clip in the lower location.. think FOX body.. fairmont, tbird 79 up mustang.. and several others.. where the neutral safety switch wiring is run along inside under the carpet or console and passes thru the floor just a few inches from the neutral safety switch... this probably saved 8 feet of wire per car.. thats a few cents more profit..  they also did not have to protect more of the wiring harness and thats labor wrapping the harness ..  

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waynep712222
User
Posts: 223
Joined: 04/13
Posted: 09/24/13 10:55 PM

that actually would be a GREAT idea for cars when you want to clean up the firewall..

hit the junk yards... find the harness that passes thru the floor on the left side of the transmission tunnel.. and use the C4 or C5 neutral safety switch so you have the proper connectors under the car..  

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momsmustang8
New User
Posts: 2
Joined: 09/13
Posted: 09/26/13 12:54 PM

I read on a post one time that there is also a wire clip mounted to the bell housing. Does anyone know anyting about that? A drawing or picture would be great. Thanks.  

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waynep712222
User
Posts: 223
Joined: 04/13
Posted: 09/26/13 03:08 PM

a similar shape to the clip seen on the side cover of the transmission...

and yes it was used..  

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