Author Topic: Manual transmission backup light/neutral safety plug  (Read 774 times)

Offline Bossbill

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Manual transmission backup light/neutral safety plug
« on: March 23, 2021, 06:39:44 PM »
On manual transmission cars the neutral safety switch wire becomes a loop since no safety switch is required (auto trans do have this requirement and a different harness).
The loop is red/blue. The backup light switch itself is black/red.

However, I have two leads and I'm not sure which one is the correct plug style for my 67. One of these black plugs is just square -- the other has a lot of extra heft for no apparent reason.
The one with the larger plug (pins are the same spacing on both) has a smaller diameter wire on the b/u and neutral wires.

In the pic below I plugged one into the other for stability while I took a pic, so ignore that.

I suspect one of these is for an earlier car.
Help identify these if you would.
Bill
Concours  Actual Ford Build 3/2/67 GT350 01375
Driven      6/6/70 0T02G160xxx Boss 302
Modified   5/18/65 5F09A728xxx Boss 347 Terminator-X 8-Stack
Race        65 2+2 Coupe conversion

Offline ruppstang

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Re: Manual transmission backup light/neutral safety plug
« Reply #1 on: March 23, 2021, 08:34:52 PM »
The larger plug is later like a C9 or service part.

Offline Bossbill

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Re: Manual transmission backup light/neutral safety plug
« Reply #2 on: March 23, 2021, 08:49:40 PM »
Thanks Marti.

My car had been modified with a Hurst so some parts were missing.
Bill
Concours  Actual Ford Build 3/2/67 GT350 01375
Driven      6/6/70 0T02G160xxx Boss 302
Modified   5/18/65 5F09A728xxx Boss 347 Terminator-X 8-Stack
Race        65 2+2 Coupe conversion

Offline midlife

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Re: Manual transmission backup light/neutral safety plug
« Reply #3 on: March 23, 2021, 10:50:46 PM »
All earlier plugs prior to 1967 were two pin affairs with separate plugs for NSS and BU lights. 
Midlife Harness Restorations - http://midlifeharness.com

Offline Blue_67_Fastback

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Re: Manual transmission backup light/neutral safety plug
« Reply #4 on: March 24, 2021, 03:25:37 AM »
Hallo Bill,
here?s mine..
enno
1967 Fastback, C Code, 3 Sp MT, 7F02C169xxx, Build Date 3/2/67
First Mustang Club of Germany 1964-73 e.V.

Offline Bossbill

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Re: Manual transmission backup light/neutral safety plug
« Reply #5 on: March 24, 2021, 01:00:24 PM »
Thanks Enno.
Bill
Concours  Actual Ford Build 3/2/67 GT350 01375
Driven      6/6/70 0T02G160xxx Boss 302
Modified   5/18/65 5F09A728xxx Boss 347 Terminator-X 8-Stack
Race        65 2+2 Coupe conversion

Offline RoyceP

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Re: Manual transmission backup light/neutral safety plug
« Reply #6 on: March 24, 2021, 01:25:21 PM »
The one used on the assembly line has a C7ZB-D sticker and has the smaller plug. The service part is C7ZZ and is more common. Both are on eBay right now.




On manual transmission cars the neutral safety switch wire becomes a loop since no safety switch is required (auto trans do have this requirement and a different harness).
The loop is red/blue. The backup light switch itself is black/red.

However, I have two leads and I'm not sure which one is the correct plug style for my 67. One of these black plugs is just square -- the other has a lot of extra heft for no apparent reason.
The one with the larger plug (pins are the same spacing on both) has a smaller diameter wire on the b/u and neutral wires.

In the pic below I plugged one into the other for stability while I took a pic, so ignore that.

I suspect one of these is for an earlier car.
Help identify these if you would.
1968 W code 427 Cougar XR-7 GTE Feb 23 Dearborn C6 / 3.50 open
1968 R code 428CJ Cougar XR-7 May 13 Dearborn C6 / 3.91 T - Lock

Offline Bossbill

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Re: Manual transmission backup light/neutral safety plug
« Reply #7 on: March 24, 2021, 02:41:08 PM »
Thanks Royce.
I liked the -D version well enough to buy it.

I'll re-assemble the one I just plated after I get the car done.
As I noted before, the one that was on the car was hacked up due to the Hurst install and I need to move on with other parts rather than futzing with this one right now.
Bill
Concours  Actual Ford Build 3/2/67 GT350 01375
Driven      6/6/70 0T02G160xxx Boss 302
Modified   5/18/65 5F09A728xxx Boss 347 Terminator-X 8-Stack
Race        65 2+2 Coupe conversion

Offline RoyceP

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Re: Manual transmission backup light/neutral safety plug
« Reply #8 on: March 24, 2021, 05:50:46 PM »
You ought to watch that particular vendor. Last month they had a number of original Autolite vacuum advance units that I snagged. I think they have access to some very old stock.


Thanks Royce.
I liked the -D version well enough to buy it.

I'll re-assemble the one I just plated after I get the car done.
As I noted before, the one that was on the car was hacked up due to the Hurst install and I need to move on with other parts rather than futzing with this one right now.
1968 W code 427 Cougar XR-7 GTE Feb 23 Dearborn C6 / 3.50 open
1968 R code 428CJ Cougar XR-7 May 13 Dearborn C6 / 3.91 T - Lock