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See attached picture. Does this harness look like the NSS harness that I need to install for my T5 transmission (which replaces the existing AOD harness that is running to through the trans tunnel)? I don't have a wiring diagram for the harness.
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Here is a picture of the two connectors that go to the AOD on my 86 GT - there are only six wires (in two connectors) running through the trans tunnel to the AOD. Wiring is as follows:
View attachment 1092603
Two Prong Black Connector: Green/White & Black/White
Four Prong White Round Connector: Black/Pink, Purple/Yellow, Red/Blue & Yellow/Pink

Do you agree that it looks like I need to get ahold of an 8-wire manual harness?
To Clarify: Two wires are running to the automatic shifter handle. So there are 8 wires in the AOD harness plug in total, 6 are running to the AOD trans and 2 are running to the shifter handle.
 

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See attached picture. Does this harness look like the NSS harness that I need to install for my T5 transmission (which replaces the existing AOD harness that is running to through the trans tunnel)? I don't have a wiring diagram for the harness.
View attachment 1092605

Here is the wire identification for the above harness

Rev = Reverse light switch
NSS = Nuetral safety jumper
VSS = speed sensor
NGS = Nuetral gear switch (top of T5)

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Here is the wire identification for the above harness

Rev = Reverse light switch
NSS = Nuetral safety jumper
VSS = speed sensor
NGS = Nuetral gear switch (top of T5)

View attachment 1092606
Thanks for the harness identification!

Here is a checklist of what I think I need to do from a wiring perspective to get the T5 to function properly in the 86 Mustang with speed density which formerly had an AOD, but am not experienced/knowledgeable enough to know if it is correct -- what am I missing? Assume the T5 trans, pedals, etc... are fully installed.

1. Replace AOD harness with a T5 harness (like in the picture). This assumes I have the correct T5 harness which I will need to verify.
2. Obtain a NGS (and install in the T5) and hook up the NGS connector in the T5 harness to the T5 Transmission.
3. Hook up VSS and Reverse connectors.
4. Find the connections for the starter clutch pedal switch & NSS, and plug them into the clutch pedal switch assembly.
5. Hook up the cruise control switch connector to the clutch pedal.
6. No need to touch the 02 harness with A9P or A9L if keeping speed density.
7. If using an A9P computer, there might be issues like hanging idle. But if using an A9L computer, there should be no hanging idle issues. Note: I currently have a used A9P that I could try out, but I don't have an A9L.
 

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See attached picture. Does this harness look like the NSS harness that I need to install for my T5 transmission (which replaces the existing AOD harness that is running to through the trans tunnel)? I don't have a wiring diagram for the harness.
View attachment 1092605
That harness is the 87-93 harness with the 87-93 T-5 pig tail attached. Will it work in an 86? Its going to be trial and error. Its going to be too long but if it does work just have to loop the wiring under the carpet somewhere.
 

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Thanks for the harness identification!

Here is a checklist of what I think I need to do from a wiring perspective to get the T5 to function properly in the 86 Mustang with speed density which formerly had an AOD, but am not experienced/knowledgeable enough to know if it is correct -- what am I missing? Assume the T5 trans, pedals, etc... are fully installed.

1. Replace AOD harness with a T5 harness (like in the picture). This assumes I have the correct T5 harness which I will need to verify.
2. Obtain a NGS (and install in the T5) and hook up the NGS connector in the T5 harness to the T5 Transmission.
3. Hook up VSS and Reverse connectors.
4. Find the connections for the starter clutch pedal switch & NSS, and plug them into the clutch pedal switch assembly.
5. Hook up the cruise control switch connector to the clutch pedal.
6. No need to touch the 02 harness with A9P or A9L if keeping speed density.
7. If using an A9P computer, there might be issues like hanging idle. But if using an A9L computer, there should be no hanging idle issues. Note: I currently have a used A9P that I could try out, but I don't have an A9L.

you only need to do 1 and 2 if you are changing out from the AOD ecu to the 5-spd ECU.

Both AOD and 5-spd cars use the same VSS and such, so this should be an easy swap. 86-88 cars use the VSS only for cruise control. Mass air cars do have an ECU connection to the VSS so the wires need to be added to pin 3 and 6 when you do a MA conversion

For step 5, the wire should be present with a jumper on it clipped to the metal support bracket near the gas pedal. Just remove the jumper and plug into the cruise disconnect plug on the pedal assemble. I recommend making sure all the cruise components are present and properly installed before installing the pedal assembly.

For 6, the o2 sensor harness jumper is a 1988+ thing. It's not present on 1987 and from what I can see also not present on 1986.

Unknown for #7 regarding the A9P. It might hang, it might not. I found it did with the A9L until i hooked up the NGS on the T5 and the only really mine wasn't hooked up was because I missed up and forgot to install the little pin under the detent ball. I wasn' dropping the trans to install that without a better reason, so I lived with it. It did it infrequently enough that it didn't bother me. Adding the pin cured it completely.


I would simplify things a lot here. Disregard the MA swap for now.

You can keep your current ECU and just hook up the clutch starter interrupt switch and the clutch NGS, and hook up the reverse light and VSS (if equipped). That will get you a running and driving 5-spd car. This will get you up and running with minimal hassle. Might you get a hanging idle from time to time? Maybe. I did.

Now, to do it factory OE correct, you'll want to track down a 5-spd 1986 speed density manual ecu. Unknown if 87 and 88 can be used. 1986 won't have the O2 sensor harness jumper. From what i see in the EVTM, it's similar to 1987 is that there is no difference in how the autos and manuals are wired for pin 30. Swap that in, install the correct trans harness that has the provision for the NGS (or run 2 wires) and that's really all that's needed.

Later on, if you want to mass air swap. Use an A9L or other 5-spd ECU, repin for the MA, and add 2 wire for the VSS (pin 3 and 6 i believe) and the single wire for the fuel pump monitor.
 

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you only need to do 1 and 2 if you are changing out from the AOD ecu to the 5-spd ECU.

Both AOD and 5-spd cars use the same VSS and such, so this should be an easy swap. 86-88 cars use the VSS only for cruise control. Mass air cars do have an ECU connection to the VSS so the wires need to be added to pin 3 and 6 when you do a MA conversion

For step 5, the wire should be present with a jumper on it clipped to the metal support bracket near the gas pedal. Just remove the jumper and plug into the cruise disconnect plug on the pedal assemble. I recommend making sure all the cruise components are present and properly installed before installing the pedal assembly.

For 6, the o2 sensor harness jumper is a 1988+ thing. It's not present on 1987 and from what I can see also not present on 1986.

Unknown for #7 regarding the A9P. It might hang, it might not. I found it did with the A9L until i hooked up the NGS on the T5 and the only really mine wasn't hooked up was because I missed up and forgot to install the little pin under the detent ball. I wasn' dropping the trans to install that without a better reason, so I lived with it. It did it infrequently enough that it didn't bother me. Adding the pin cured it completely.


I would simplify things a lot here. Disregard the MA swap for now.

You can keep your current ECU and just hook up the clutch starter interrupt switch and the clutch NGS, and hook up the reverse light and VSS (if equipped). That will get you a running and driving 5-spd car. This will get you up and running with minimal hassle. Might you get a hanging idle from time to time? Maybe. I did.

Now, to do it factory OE correct, you'll want to track down a 5-spd 1986 speed density manual ecu. Unknown if 87 and 88 can be used. 1986 won't have the O2 sensor harness jumper. From what i see in the EVTM, it's similar to 1987 is that there is no difference in how the autos and manuals are wired for pin 30. Swap that in, install the correct trans harness that has the provision for the NGS (or run 2 wires) and that's really all that's needed.

Later on, if you want to mass air swap. Use an A9L or other 5-spd ECU, repin for the MA, and add 2 wire for the VSS (pin 3 and 6 i believe) and the single wire for the fuel pump monitor.
Thanks, Mike. I super vote for simplification here.

Do you know if the attached photo of this VM1 will quality as a ECM for the 1986 speed density manual ecu? I bought it several years ago along with some other parts and just realized I had it.
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Now, to do it factory OE correct, you'll want to track down a 5-spd 1986 speed density manual ecu. Unknown if 87 and 88 can be used. 1986 won't have the O2 sensor harness jumper. From what i see in the EVTM, it's similar to 1987 is that there is no difference in how the autos and manuals are wired for pin 30. Swap that in, install the correct trans harness that has the provision for the NGS (or run 2 wires) and that's really all that's needed.
I like this OE correct option the best if I can make it work. Remember you helped me understand that there are 8 wires in the existing AOD harness connector inside the car and we identified (if I understand correctly) that there are 2 wires running from the connector to each of:

Rev = Reverse light switch
NSS = Neutral safety jumper
VSS = speed sensor
Automatic shifter assembly

Here is my question/confusion: If I run 2 new wires (instead of getting a T5 harness) to the harness for the NGS (neutral gear switch at top of T5), I will be adding the 2 wires to the existing AOD harness that runs through the trans tunnel, the 2 wires will go to the NGS on the trans, but where will they hook to inside the car?

It wouldn't make sense for these 2 new wires to run into the 8 pin connector in place of the wires that previously served the automatic shifter. I suspect this is where having a manual might help me out, but the more I read the more I it appears that the manual might not be that helpful.
 

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This is where you do need the manual. Kinda need to get in the car and trace things out and verify colors on the EVTM.

It’s clear to me there are enough differences in how 86 routed the wires vs 87+ that I shouldn’t make assumptions on how a circuit runs.
 

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I forgot a circuit.

So should be 8 wires.

2 for backup
2 for VSS

those match the EVTM.

the wire colors for the VSS don’t match up. There’s two for those. Then there should be 2 for the NGS on top of the t5. I can’t find those wire colors in the EVTM, but Ford did a terrible job diagramming that out on the 87-93 cars as well and the EVTM is actually incorrect.

anyway, it’s possible since your have 8 wires in that plug, that you might already have the plug for the NGS present. Have you gone under the car and verified if it is in fact there? My 88 aod car only had 6 wires in the harness so I had to swap to the 8-wire manual harness, but it looks like yours might not need to be changed.

ultimately that’s what drove us on this hunt right? Adding the correct harness for the NGS?
When you swapped in the 8-wire T-5 harness, did you just unplug the AOD harness and plug the T-5 harness in? What year is the car you did the T-5 swap in?
 

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Mine is an ‘88. I swapped it to a 5-spd and then later mass air (A9L)

I just plugged it all in. Nothing else really needed.

when I did my MA swap I went from AOD SD ECU to the 5-spd MA ECU. I had to change the o2 sensor harness jumper, but like I said, that’s an 88+ issue.
 
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