Wiring Clutch Switch, Reverse Lights, NSS from 3.8 v6 to 5.0 swap

[strtcar]

Car - 1986 Mustang LX 3.8 v6 CFI, C5 Auto...converting to 5.0/t5/Holley Terminator X EFI

Long time listener first time caller here....

Doing a 5.0/T5 swap into an 86 v6 auto....Going with aftermarket EFI, so I've ripped harness from passenger side, now working on sorting out what I need to keep on driver side.

I'm trying to figure out the Start/NSS/Clutch/Reverse light situation, I've read you can just plug pigtails from auto car into clutch pedal but I dont think I have those in my early 86 built car, so likely need to build my own wire harness.

What I'm planning so far the following:

Reverse Lights - I have 4 wires going to the orig trans tunnel, I believe the Purple & Black wires are reverse lights, so buy a new plug for t5 trans and plug into side of trans.

NSS - the old NSS wire from auto, as part of the reverse light harness (Red/Light Blue loop together with White/Pink), I think I just loop those two together? I don't need the T5 NSS because the Holley EFI won't need that.

Clutch Switch - This is where I'm lost as to what is needed?

Thanks for any help.

[wraithracing]

First congratulations on your first post on FEP. I would recommend either stating what year model you are working on in your post or putting that information in your signature. The wiring is similar for the 79-86 cars in many ways, but there were lots of changes over the years and differences between engine/trans combinations. That will help others provide you with more accurate information.

The automatic NSS/Reverse Lights harness is not a plug and play with the 5 speed cars. The wiring does not match up correctly. Unfortunately I have performed a swap or done the rewiring in several years now, so my memory of the exact wire colors is a bit hazy.

I believe the Purple and Black wires are the reverse lights, but I would double check the Electrical Diagram sticky here on FEP to verify. Same for the other wires. In the 5 speed application the clutch switch is simply nothing more than completing the circuit for the ignition so the starter can engage. So you have the Clutch switch that is mounted on the clutch pedal starting I believe in late 1983 that the wire runs up to the clutch switch and when the clutch is not depressed the circuit is open. When you depress the clutch that completes the circuit and allows the power to flow to the starter so the engine can be fired up. I believe the red/light blue wire is what you need. I want to say that the white/pink wire is not needed, but that could be the other side of the harness. I have never owned a 3.8 V6 car, so not familiar with the wiring. Good Luck!

[strtcar]

@wraithracing, thank you for the reply and confirming a few things for me. I have updated the post with more car details. And thanks for simplifying my thinking on the clutch switch simply being something that completes the circuit, I'll do some testing on it to understand further. Any idea what connector I can use to connect into that switch, considering I don't have any factory connectors want to buy the right one as I rewire.

[wraithracing]

I am not sure on the 86 V6 model, but the 86 5.o EFI wiring harness was a one year only harness due to the EFI that year. I have a full 86 5.0 EFI body harness that I removed from a car many years ago. If I have time to find it in my multiple boxes of wiring, it may still have the clutch switch wiring on it. Not sure when I will have time with the holidays, etc. but I will try and take a look.

I don't remember what the connector is for the clutch switch off hand, again its been awhile since I did any clutch switch wiring work on a Fox. Here is the actual clutch switch itself. https://lmr.com/item/LRS-11156A/86-9...-Safety-Switch it was used all the way until 2004, so if you have salvage yard near you with any Mustang, you might be able to get a switch, the plug and the wiring off a donor car and then splice into your harness. The wire colors may be different due to year model, but the switch is the same.