Wiring Help and question

old parts man

Member
Apr 28, 2021
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Lex Ky
Hey group, old parts man here.

I have a 67 coupe Auto trans , 2 V. I've hit a blank wall. I removed all the seats and carpet out, when I pulled the drivers seat out there was a ground wire laying under the carpet, it comes from the left rear stop light, it has the original clip that connects to the housing on the stop light. I eveindently pulled it loose from under the dash, can't find where it hooks back up. I don't unerstand why they would bring a ground wire fron the back to the front. Anyone have seen this before? I have the original Ford shop manuals and schematics books, can',t find a thing about it. Need some help.
 
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Husky44

10 Year Member
Sep 27, 2006
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I am NOT the guy you want, to take electrical advice from, but I read recently when working on my wiring that ground to the tail light is used to signal something with interior lights (IIRC) that only come on in certain situations (eg, interior lights or dash lights that only come, on when tail lights are on).

Look at your schematics with that in mind. If you can't find it let me know and I'll dig through my notes and references in the garage.
 

old parts man

Member
Apr 28, 2021
6
1
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80
Lex Ky
I am NOT the guy you want, to take electrical advice from, but I read recently when working on my wiring that ground to the tail light is used to signal something with interior lights (IIRC) that only come on in certain situations (eg, interior lights or dash lights that only come, on when tail lights are on).

Look at your schematics with that in mind. If you can't find it let me know and I'll dig through my notes and references in the garage.
Thanks for the input, I've worked on this for 2 days and gone over my schematics again and again, just can't find where it grounds. I've lost the dash cluster lights.
 

wicked93gs

15 Year Member
Sep 30, 2006
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Nashville TN
66-ext-lights-diagram-jpg.802135


It looks like 14 is the circuit you are talking about, its a bullet connector that connects to the headlight switch? Do you have a picture of the wire in question?
 
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old parts man

Member
Apr 28, 2021
6
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Lex Ky
66-ext-lights-diagram-jpg.802135


It looks like 14 is the circuit you are talking about, its a bullet connector that connects to the headlight switch? Do you have a picture of the wire in question?
That might just be what I'm looking for. For some reason I over looked this one.. No picture of the set up. I'll check this ground tomorrow and let you know. Thanks
 

Husky44

10 Year Member
Sep 27, 2006
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That might just be what I'm looking for. For some reason I over looked this one.. No picture of the set up. I'll check this ground tomorrow and let you know. Thanks
FWIW, the 67 diagram is drawn differently than the one @wicked93gs posted above, but looks to be functionally the same for your purposes. I knew that ground on the taillight did something under the dash. Not as dumb as I look! :D
 
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old parts man

Member
Apr 28, 2021
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Lex Ky
I believe that's it, I'll find out today.
Husky 44 this is correct, just put in a new headlight switch, it's good to go. For some reason I checked the ground wire #14 on the diagram, on my old headlight switch and when I turn on the headlights the plug goes hot, still same way with my new headlamp switch. Now I'm afraid to connect the ground wire from the rear tail light into the ground wire bullet connector. . That can't be correct, and I'm lost on where to look for the short. I've never had a ground wire hot.
 

WORTH

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The only light with a separate ground would be the headlight, If you have a ground from the tail light bucket I would assume a previous owner had a grounding issue and brought it right to the front to insure a good ground, that wire can be grounded anyplace you would like. And might I add, you can never have too many grounding points.
 
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