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Ok, looks like ford still routed the three circuits through the same harness like the 87-93 cars, but the location of the plug is different. It comes up the trans tunnel and connects center of the dash behind the center of the instrument panel(th is might mean dash) , not the kick panel.

black 8-pin plug, C350 on the wiring diagrams . Cannot locate a diagram showing the location.

for wire colors:

VSS: black/white stripe, Dark Green/white stripe
Backup lights: purple/orange stripe, black/pink stripe
Neutral safety: white/pink, red/lt blue

Unsure if the other two spots on the 8-pin connector are occupied, so possibly 6 wires in a black 8-pin connector. See if you can locate it under the dash. I’ll update if I find more info

still unknown if the 87-93 harness would work. Would need to see the 86 harness first
 
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Ok, looks like ford still routed the three circuits through the same harness like the 87-93 cars, but the location of the plug is different. It comes up the trans tunnel and connects center of the dash behind the center of the instrument panel(th is might mean dash) , not the kick panel.

black 8-pin plug, C350 on the wiring diagrams . Cannot locate a diagram showing the location.

for wire colors:

VSS: black/white stripe, Dark Green/white stripe
Backup lights: purple/orange stripe, black/pink stripe
Neutral safety: white/pink, red/lt blue

Unsure if the other two spots on the 8-pin connector are occupied, so possibly 6 wires in a black 8-pin connector. See if you can locate it under the dash. I’ll update if I find more info

still unknown if the 87-93 harness would work. Would need to see the 86 harness first
Here is a pic of the harness coming from the trans tunnel. Nothing was hooked up to the single black connector.
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How many wires are in that plug and what are the colors?

I see more than 6. Possible you already have the connection for the NGS?
 

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How many wires are in that plug and what are the colors?

I see more than 6. Possible you already have the connection for the NGS?
8 Wires total. The wiring diagram should be close on the colors, but it's hard to tell because they are faded. For Example: "Black White" means Black wire w/ white stripe. The wires coming from the trans are on the left side; wires coming from the car-side are on the right side.
 

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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?
 

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It’s also entirely possible that it’s not used the same way as the 87+ cars. The more I look through the EVTM the more differences I spot. Like I said, I’m pretty good with 87-93 wiring but pre-87 stuff I’m still just figuring it out along with the rest of you.

I will say though that Ford improved how it wrote the EVTMs as the years went on.
 

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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?
I will put it on a lift this weekend and see what connectors are there, and will report back - thanks!!
 

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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?
Yes, my goal is to have the 86 GT set up like factory, i.e., it will only start when the clutch is pressed to the floor.
 

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Yes, my goal is to have the 86 GT set up like factory, i.e., it will only start when the clutch is pressed to the floor.
Let me clarify, I want to wire it so it won’t start unless the clutch pedal is pressed in. I don’t care about it being in neutral to start. I’m at a loss without a wiring diagram, but I am guessing the clutch pedal safety switch on the clutch pedal is all I need hooked up and wired properly to accomplish my goal, correct?

Also, is the cruise control at all impacted by any of this wiring? My cruise works and I want to keep it working!
 

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The 5-spd cars bypass the NSS that is normally used on the AOD cars. It gets jumped out on the reverse harness pigtail. Red wire with blue stripe.

the connector on top of the T5 is called the NGS or nuetral gear switch. It’s not a nuetral safety. The 5-spd cars rely on a clutch starter safety switch and those plugs are tucked under the dash over near where the clutch pedal hangs. Just need to remove the jumper and plug them in.

the NGS May affect idle quality and cause a hanging idle on “some” cars if left disconnected. My car had this issue which was cured by plugging in the NGS. Other cars run perfectly fine without it.

since I’m all about keeping wiring and such as close to OE correct with little variation, I recommend putting in the effort to see what it would take to hook it up proper. I also typically recommend using a 5-spd ECU. Again some folks never have an issue with the aod stuff, but I did. I left the NGS unhooked and ran the aod ECU. Every once in a while I had hanging idle issues that I could never solve. Finally I swapped to the correct 5-spd wiring first and then an A9L and all that went away and the car has never run better.
 

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The 5-spd cars bypass the NSS that is normally used on the AOD cars. It gets jumped out on the reverse harness pigtail. Red wire with blue stripe.

the connector on top of the T5 is called the NGS or nuetral gear switch. It’s not a nuetral safety. The 5-spd cars rely on a clutch starter safety switch and those plugs are tucked under the dash over near where the clutch pedal hangs. Just need to remove the jumper and plug them in.

the NGS May affect idle quality and cause a hanging idle on “some” cars if left disconnected. My car had this issue which was cured by plugging in the NGS. Other cars run perfectly fine without it.

since I’m all about keeping wiring and such as close to OE correct with little variation, I recommend putting in the effort to see what it would take to hook it up proper. I also typically recommend using a 5-spd ECU. Again some folks never have an issue with the aod stuff, but I did. I left the NGS unhooked and ran the aod ECU. Every once in a while I had hanging idle issues that I could never solve. Finally I swapped to the correct 5-spd wiring first and then an A9L and all that went away and the car has never run better.
I fully agree with trying to keep the wiring OE, which helps troubleshooting in the future. I will dig into this more when I get the EVTM manual I ordered. I should also look at the best ECU option because I want to avoid future problems. Also, I was thinking of staying with speed density, but could switch to mass air. I am trying to make this a good, reliable driver.
 

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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.
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:
Automotive lighting Automotive tire Hood Motor vehicle Vehicle

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?
 

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I'd like to know the manufacture date of your 86'? Because it has the large connector harness plug for the AOD like from the early 80's up to 85' cars I thought. Maybe they extended the use of these connectors into early 86'. Is it an early in the year production 86'? I happen to have a T-5 wiring harness pig tail for that large plug connector if you end up keeping the harness that's in the car.
 

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I'd like to know the manufacture date of your 86'? Because it has the large connector harness plug for the AOD like from the early 80's up to 85' cars I thought. Maybe they extended the use of these connectors into early 86'. Is it an early in the year production 86'? I happen to have a T-5 wiring harness pig tail for that large plug connector if you end up keeping the harness that's in the car.
If the driver's door is original to the car (which I can't confirm because I have not owned it since new) it says it was manufactured on 09/86.
 
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