Jump to content
smh00n

TKO conversion - back up switch and neutral start hacks

Recommended Posts

Ladies and Gentlemen

I am into the wiring for my TKO conversion from an auto, and just needed some hand-holding before I chop wires up. The car has been hacked up especially in the back so I don't want to spend nights pulling wires and hair out.

From this thread I see I am looking for a black and red wire into a 4 wire connector (labelled "H") at the firewall to plug the back up switch from the trans into. Yes? I guess there is power into this switch from the 296 wire out of the fuse box? So I need to make sure 12V is on one side?

And then, in back I have the same single red/black wire to power the reverse lights. Yes?

Next, I have seen you basically jump the original neutral start wiring to bypass the original automatic gearlever switch. Can someone give me wire colours to jump? I have a single wire and also a block of about 4 that came off the auto.

Last, can you buy the OEM moulded plugs? I have LED lights for the hood turn signals, but they have been hacked before from the harness plug, so I was going to make a new harness; but I don't have any of the original plugs used. I can use dodgy connectors but prefer not to.

 

Share this post


Link to post
Share on other sites
12 minutes ago, Midlife said:

NSS wire colors are red/blue.

Most Ford molded connectors are standard trailer connectors.  You can find many of them with pigtails (but not with the correct Ford wire colors) at https://www.delcity.net/store/Molded-Connectors-without-a-Loop/p_8593

Thanks - they are in the same plug by the looks of it?

I looked again the the hood turn signals. They have cut the original wiring...

I have  a couple of single connectors near the 4 way NSS/reverse plug. One has gray wire. One I remember went to the auto shifter. Is that just a light power switch? 

Share this post


Link to post
Share on other sites

I am jumping in to the middle of this thread, so just ignore it if this is not helpful....

You can permanently or temporarily bypass the NSS by connecting the two Red- Blue Stripe wires together in the four pin plug coming from the firewall. It the same as the loop-back Ford used on manual cars. I bought the manual safety switch wire harness for my Tremec. It had the correct factory 4 pin plug on the one end and the tremec plug on the other.

1971195928_FirewallHarnessPlugs.thumb.jpg.47f5f16aabbeb7c45642ebafde39990b.jpg

 

 

Ford Charging & Prove-Out with Tach Wiring Diagram.jpg

s-l400.jpg

1970 Mustang Exterior Lights Wiring Diagram P1 & P2.jpg

Share this post


Link to post
Share on other sites
On 3/5/2023 at 9:52 PM, smh00n said:

Ladies and Gentlemen

I am into the wiring for my TKO conversion from an auto, and just needed some hand-holding before I chop wires up. The car has been hacked up especially in the back so I don't want to spend nights pulling wires and hair out.

From this thread I see I am looking for a black and red wire into a 4 wire connector (labelled "H") at the firewall to plug the back up switch from the trans into. Yes? I guess there is power into this switch from the 296 wire out of the fuse box? So I need to make sure 12V is on one side?

And then, in back I have the same single red/black wire to power the reverse lights. Yes?

Next, I have seen you basically jump the original neutral start wiring to bypass the original automatic gearlever switch. Can someone give me wire colours to jump? I have a single wire and also a block of about 4 that came off the auto.

Last, can you buy the OEM moulded plugs? I have LED lights for the hood turn signals, but they have been hacked before from the harness plug, so I was going to make a new harness; but I don't have any of the original plugs used. I can use dodgy connectors but prefer not to.

 

Here is the way I wired the NNS and Backup Lights Switch on my factory 1070 Mach 1. Manual 3 and 4 Speed cars had basically the same NSS/Backup Light harness out thru the firewall  to the four pin plug. Automatics had the NNS safety switch harness to the trans, whereas manual shift cars had a loop back wire in the plug on the trans side. If you wan the NSS to function with your Tremec TKO, then you will need The Tremec NSS harness, and the Tremec to Ford Backup Light harness, (Scott Drake has a nice one). Also some 14 AWG wire ( blank ground wire) and a 4 or 5 terminal 12v 30 amp Relay and some blade connectors or matching relay plug (a mounting bracket optional). The relay is  needed because the NSS will trip the relay on or off when it completes or disconnects the  the ground circuit, which in turn will connect or disconnect voltage to the starter solenoid. I read that you should not pass 12v thru the Tremec NSS, if you do it will eventually stop working. 

Fish one or two ground wires  thru the Tremec to Ford Backup Light harness (only need to fish one wire thru the harness if you ground the second wire in the harness to the undercarriage near the Tremac). I brought both ground wires to the the firewall. One near the four pin plug and the other I grounded to the firewall with the wiper ground wire. One NSS ground wire goes to relay terminal 30 and the other as mentioned before to the chassis ground. If the Backup Light harness four pin plug has the red/blue striped loopback wire cut the loop wire in half so yo have equal wire lengths. Identify which of the two Red/Blue striped wires that you just cut is coming from the ignition key/switch side and mark it as such and connect it to the 30 terminal on the relay. Make a 3 inch pigtail wire when crimping the relay terminal spade to the end of this Red/Blue striped wire and connect the pigtail to the relay's 86 terminal. Finally, connect the other Red/Blue striped wire you cut to terminal 87.  Here is a diagram of what I just described...

And a Video explanation... 

https://www.google.com/search?q=tremec+nss+operating+instructions&rlz=1C1RNOE_enUS743US744&sxsrf=AJOqlzWMKee-Og6jW4d4Lx6FuN1Jjrw-TA%3A1679098093900&ei=7QAVZNfMNrOpptQP7Ye_iA4&oq=tremec+nss+oper&gs_lcp=Cgxnd3Mtd2l6LXNlcnAQARgAMgUIIRCgATIFCCEQoAEyBQghEKABOgoIABBHENYEELADOgUIIRCrAkoECEEYAFCED1jrMGDoSmgBcAF4AIABtgGIAcADkgEDMi4ymAEAoAEByAEIwAEB&sclient=gws-wiz-serp#fpstate=ive&vld=cid:50bbc5eb,vid:lJ8B6Iim_F4

 

My NSS Backup Lights Wiring For Tremec TKO.jpg

Share this post


Link to post
Share on other sites

Phew. Super mind-bending day at work and just read this. I appreciate it, have not thought about keeping the NSS active but probably not a bad idea. The video is simples, nice easy bit of work.

I'll digest it later when my brain is not telling to go to the fridge and take 3 beers in quick succession (like a Doctor says take some pills and call me later, beer fixes my issues)

 

Share this post


Link to post
Share on other sites
6 hours ago, smh00n said:

Phew. Super mind-bending day at work and just read this. I appreciate it, have not thought about keeping the NSS active but probably not a bad idea. The video is simples, nice easy bit of work.

I'll digest it later when my brain is not telling to go to the fridge and take 3 beers in quick succession (like a Doctor says take some pills and call me later, beer fixes my issues)

 

I am with ya... I needed 3 beers after writing that darn post. Let me know if I can clarify anything. 

The video created by American AutoWire is a bit more generic and they use their wiring kit as a reference point. I still have the original Ford wiring harnesses in the car, so I created the diagram using the Ford wiring diagram as a reference point. It helps me keep things in context, because I will surely forget what I did a month later and have to spend time retracing my steps to refresh my memory. 

Share this post


Link to post
Share on other sites

....Or, you could just buy one of these. Amazing what you find when you search 1970 Mustang back up switch harness.

This looks like it is made/supplied by Scott Drake, it is a 4 speed harness and has the correct plug. $40US is a bargain I reckon.

IMG_5515.thumb.JPG.aed6a5f428f7e742a71e3992335c6e70.JPG

 

One supplier told me it had been discontinued so lucky another one had stock. The manufacture date is 2016 so it may well be obsolete.

Looks good, it has the NSS loop

IMG_5518.thumb.JPG.16c570aae2e4ec62545933cdaaf259d5.JPG

IMG_5516.thumb.JPG.3c03cc2ca249de3adf5b71652389bb70.JPGIMG_5517.thumb.JPG.e88747b35206de071ee6a8de0e84e375.JPG

Share this post


Link to post
Share on other sites

Good intel. I will look at doing the NSS. Along with the fact it's a stick, that might confuse the kids who might attempt to boost it when I'm parked on the street.

Share this post


Link to post
Share on other sites
5 hours ago, smh00n said:

Good intel. I will look at doing the NSS. Along with the fact it's a stick, that might confuse the kids who might attempt to boost it when I'm parked on the street.

If you have fuel injection, you could use a second relay to cut voltage to the fuel pump while in Neutral and you are not priming the pump.

Share this post


Link to post
Share on other sites
8 hours ago, smh00n said:

I have Holley Sniper and it has a ground wire that I have hooked up. Engine turns over, does what it is supposed to do except fire. 

Just out of curiosity did you ground the white wire in the 10 pin plug to kill the engine? What ignition system are you using?

Share this post


Link to post
Share on other sites

Yes, the white wire I have connected to the cigarette lighter. Push it in, grounded. Sneaky, right? Except now the whole world knows....

I am using all MSD ignition; billet distributor, 6AL CDi box all hooked up to the Sniper. Effortless, never had an issue.

Share this post


Link to post
Share on other sites
On 4/1/2023 at 6:34 PM, smh00n said:

Yes, the white wire I have connected to the cigarette lighter. Push it in, grounded. Sneaky, right? Except now the whole world knows....

I am using all MSD ignition; billet distributor, 6AL CDi box all hooked up to the Sniper. Effortless, never had an issue.

Why would you need the ground ? What purpose does it serve ?

Share this post


Link to post
Share on other sites
6 hours ago, Mach1 Driver said:

As I recall, with the white wire grounded it doesn't get an RPM signal so the EFI stays off.

Not sure the exact process and what it affects, but it's part of the MSD box so the engine cranks as per normal but just does not fire. The fuel pump runs, the sniper  dash lights up, all looks normal. Just an in-built kill switch.

Great idea, except when you forget you switched it and you try starting your car with everyone within a mile radius watching your every move.

Share this post


Link to post
Share on other sites

I know I'm late to the party, but I have a TKX in my 1970 and hooked up the neutral start switch and the back up light switch to my car's stock wiring.  I took the wire from a C4 neutral start switch wire harness and cut off the switch.  I bought a Tremec style back up light switch plug and the plug to mate to the TKX's neutral start switch.  I just wired them in to the C4 neutral start switch harness.  I ended up with a very clean setup that works great.  I don't have any pics of the wire harness I made, but you can see the back up light switch plug on the left side of the transmission and on the right side above the transmission mount you can see the connector for the neutral start switch.

 

 

TKX installed.jpg

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...